Notes on Codecademy “Learn Bash Scripting”

After a frustrating time with Codecademy’s “Learn Sass” practice projects, I poked around the course catalog for something quick and easy to go through. I saw the “Learn Bash Scripting” course which had just a one-hour estimate for time commitment. Less than an hour later, I can say it met expectations: it was quick and easy covering a few basic things, leaving plenty more for me to learn on my own if I wanted to.

Technically speaking I’ve already been making shell scripts to automate a few repetitive tasks, but they have all just been lists of commands I would have typed at the command line. Maybe an echo or two to emit text, but no more. If I had needed to automate something that required decision-making logic, I used to go to something like Python. Which works but rather heavyweight if all I wanted was, say, a single if statement in reaction to a single user input. I could have done that with a shell script.

And after taking this course, I know how. One of the first things we saw was if/then/else/fi. There is a limited set of logical operators available, along with warnings that spaces are consequential. (One extra space or one missing space become syntax errors.) Getting user input from a read is straightforward, though parsing the resulting string and error-handling weren’t covered. We also got to see loop commands for, until, and while. What we did not cover in this course were how to define functions to be called elsewhere in the script in order to reduce repetition. That was the only thing I wished the course covered. If I wanted to do anything more sophisticated that the above, I would likely go to Python as I used to do.

The practice project associated with this course was touted as a “build script” but it’s not a makefile, just a series of copy commands interspersed with a bit of logic. I was a little annoyed it assumed we knew command line tools not covered in class, like head and read, but I’ve learned about them now and I could add them to my command-line toolbox.

Problems with Codecademy “Learn Sass” Projects

I revisited Codecademy’s “Learn Sass” class for a quick review and also to check out new material added since my first run. I’m also a Codecademy Pro subscriber this time, which opened up the practice project assignments. The lessons went fine, but the projects did not. The learning environment was supposed to automatically compile SCSS to CSS every time I hit “Run”. But it was quickly obvious that changes I made to SCSS file were not being reflected in the corresponding CSS file nor visible in HTML. Is it another back-end failure like what foiled my Codecademy MongoDB course? Some debugging later, I figured out the problem: if I make a mistake in the SCSS file and create invalid Sass syntax, the background compiler runs and fails. This is a part of learning and is OK. What is NOT OK is the fact it silently fails without showing me an error message. This infuriating behavior is not the first time Codecademy did this to me. Fortunately, this time project material is easy enough for me to port elsewhere.

The quickest and easiest (if not the most efficient) way to do this was to fire up Visual Studio Code and tell it to build me a dev container. I could replicate most of this functionality on my own, launching a Node.js Docker container instance and mapping a volume to my GitHub repository working directory. But by using a published configuration file for Node.js JavaScript projects, I was up and running in a half dozen mouse clicks and much quicker than doing it on my own. After the container was up and running, I followed Sass installation directions to run npm install -g sass. Now I could run sass compiler myself and get error messages to help me fix my mistakes.

Even with that, though, I’m not out of the woods. This course is several years old and shows signs of lacking maintenance. One project stumbled into deprecated behavior that generated compile-time warnings.

Deprecation Warning: Using / for division outside of calc() is deprecated and will be removed in Dart Sass 2.0.0.

Recommendation: math.div($tons-produced, 3) or calc($tons-produced / 3)

More info and automated migrator: https://sass-lang.com/d/slash-div

   ╷
54 │     height: #{$tons-produced/3}px;
   │               ^^^^^^^^^^^^^^^^
   ╵
    main.scss 54:15  root stylesheet

Fortunately fixing this one is fairly easy, following the recommendation to wrap the calculation inside a call to calc(). But then it gets worse: we get a non-obvious error.

Error: Undefined operation "null % 3".
   ╷
56 │     @if($i % 3 == 0){
   │         ^^^^^^
   ╵
  main.scss 56:9  root stylesheet

I understand the intent of the project, but I don’t know why this code isn’t working. Even after I copied directly from the answer key to verify I’m not just making a silly typo somewhere. $i was defined in the @each loop and we could use at the top level of the loop successfully. But this line is in an inner scope and using $i is an error here. My hypothesis is that I stumbled into a Sass breaking change regarding variable scopes.

Even if I ignore these technical errors, I’m not terribly fond of these projects. This particular error was from a project using CSS to build bar charts. Would anyone actually do this? It feels like a pointless demo showing something could be done but not something actually useful. Due to this and the fact we are looking at old material, I didn’t get as much out of these projects as I had hoped. I shrug and move on.

Notes on Codecademy “Learn Sass”

Reviewing what’s new (and relevant to me) with Angular over the past two years, I saw improved support for Sass listed. As soon as I saw that, I realized I should review Sass before diving into Angular again. Codecademy has a “Learn Sass” course and based on my notes here I’ve taken it once years ago. My Codecademy progress tracker page showed the course as “Completed” as well. But when I clicked “Start”, my progress bar dropped to 41% complete. This is because the course had a few updates in the “Sustainable SCSS” section. There’s also the fact that my previous run was without a Codecademy Pro subscription, so I didn’t have access to the projects section of the course.

Reviewing the Lessons turned out to be quite useful, as I had forgotten some of Sass and other pieces took on a different meaning in light of other recent classes I’ve taken. Notable Sass features include:

  • Nesting: the course started with nesting clauses, which is still my favorite part of Sass and probably still the biggest value added. Keeping related CSS rules together in a parent/child hierarchy helps understand organization in a style sheet, we no longer have to memorize which rules we’ve seen elsewhere.
  • Variables: The Sass variables mechanism isn’t exactly the same as CSS variables a.k.a. custom properties, but they solve many of the same problems. Historically, Sass variables existed before CSS variables support were widespread among browsers.
  • Functions: Sass functions also start with a fixed set just like CSS functions. (We can’t declare our own functions.) But Sass goes further by giving us features like loops and if/else which I haven’t seen from CSS functions.
  • Mixin: The final major Sass feature I liked. A @mixin is a CSS macro that we can then use elsewhere in the style sheet via @include. As demonstrated in the course, this is great for packing all different vendor prefixes into a single line.

The course covered other topics, but they didn’t stand out as much to me. Maybe I’ll value them after tackling more projects. I’m curious if the best practices recommended in “Sustainable SCSS” would be very practical elsewhere, especially something like Angular which imposes its own project file structure.

So the lessons review were fine, and now with a Pro subscription I wanted to give the projects a shot. I ran into problems immediately: my changes in .scss file did not reflect on .css, nor are changes visible in rendered HTML. What’s going on? Time for some debugging.

A Quick Look at Angular 15

In the interest of improving the odds that I’ll actually learn something I can put to use, I’ve devised a plan for how I intend to learn and apply Angular application framework. My skills have evolved since the last time I ran through Angular tutorial, and it’s no surprise that Angular has evolved itself. Web technologies move fast! My previous effort worked with Angular 11, and as of about two weeks ago, we’re now up to Angular 15. I looked through the changes to see how much I understood and how much would actually affect the kind of projects I intend to build. It appears that I picked a good time to review Angular — v15 looks to be quite a consequential step forward.

From the “Angular v15 is now available” (2022/11/16) page:

  • Standalone components: I got excited about this item because I didn’t understand Angular terminology. I thought “standalone” meant I could use Angular components piecemeal independent of the Angular framework, I was wrong. Reading more, I’ve learned some people felt Angular components are too dependent on a specific Angular mechanism “NgModule”. Architecturally that meant a NgModule was the smallest unit of reusability, and not Component as intended. This “standalone” feature makes it easier for an Angular Component to run without NgModule.
  • NgOptimizedImage: Sounds like the Angular framework can now handle resizing image files. So large screen desktops don’t get blurry images and small mobile devices don’t waste bandwidth downloading high resolution images.
  • Stack traces are more helpful: Sounds promising. Getting an informative stack trace has always been a problem with debugging asynchronous code.
  • MDC-based components: Angular Material was why I started looking at Angular framework to begin with! At the time it was an Angular-focused set of web controls that are implemented differently from those intended for non-Angular web sites. (The non-Google affiliated Materialize-CSS project was something I’ve tried along similar veins.) Now it seems like the two worlds are converging, nice.

From the “Angular v14 is now available” (2022/6/2) page:

  • Strictly typed forms: Reading the description, it’s the kind of thing that surprised in the “Wait, you meant it wasn’t like that already?” category. Angular uses TypeScript and leverages its compile time type checking to catch bugs. Given this fact I was surprised that forms (a major way to interact with user data) aren’t strictly typed. Perhaps there’s subtlety here I don’t understand but better type checking is almost always a good thing.

From the “Angular v13 is now available” (2021/11/3) page:

  • End of IE11 support: This only impacts me because I have a bunch of old Windows Phones that I had intended to reuse in other projects via its integrated web browser, which is a mobile build of Internet Explorer. Angular 11 didn’t officially support IE but it was possible to build for IE with a few project settings. The results… mostly worked. As of Angular v13 that is no longer an option. If I still want to put those old Windows Phones to work via web apps, I’d have to do it with older versions of Angular or without Angular at all.

From the “Angular v12 is now available” (2021/5/12) page:

  • Sass: I had forgotten about Sass until I read Angular v12 increased support for Sass. I learned about Sass quite some time ago, before my recent efforts to relearn CSS. I’ve forgotten much of Sass and how it addresses challenges of plain CSS. I’m going to refresh my knowledge of Sass before I proceed.

Notes on TypeScript Handbook

I liked the idea of TypeScript, a tool that makes JavaScript more predictable and manageable. An introduction from Codecademy’s Learn TypeScript course was quite instructive, but I knew that wasn’t the whole picture. To learn more, I decided to read through the TypeScript Handbook. It is a document meant to be shorter and easier to read than the formal TypeScript language definition, at a tradeoff of less precision and skipping over details on edge cases.

The majority of value in TypeScript is in keeping track of code intent by assigning data types to variables. At first glance I thought it would be helpful but not a huge deal, but I was wrong. TypeScript can infer a lot from these type assignments. My favorite example was named “Exhaustiveness checking“, where TypeScript could infer when a switch() statement is missing a case. This is a class of problem I frequently try to make visible in my own code. Unfortunately, I could only log an error and/or throwing an exception in case I fall into default. Which is a runtime solution where my code would come to a screeching halt long after I wrote it. But with TypeScript exhaustiveness checking combined with TypeScript ‘never‘ Type, I could turn such mistakes into compile-time error “is not assignable to type 'never'“. This is huge and this capability alone is enough to turn me into a TypeScript fan.

However, TypeScript can’t solve all JavaScript ills, because TypeScript always maintains full runtime compatibility with JavaScript. This means TypeScript labels like “readonly” only communicates intent for compile-time checking and could not guarantee the value will remain immutable at runtime. It couldn’t solve the fact JavaScript evolution ended up with a very convoluted model on what “this” means. Sometimes TypeScript tries to solve a problem, only for JavaScript to end up with a different solution to the same problem. Such as TypeScript labeling class members as private (intent-only compile time check) and JavaScript’s “#” private marker (actual runtime enforcement?) And if JavaScript changes how inherited fields are initialized, TypeScript must follow suit while doing their best to provide a mitigation for existing code.

Another area where TypeScript had no choice but to follow suit with JavaScript is adopting all the different ways a function could be declared. My eyes started watering as I read through the function section of TypeScript handbook, I had never even seen most of these ways! Designing TypeScript so it could annotate type information on all of these function declaration methods must have been a huge headache. But this was just a taste: there’s a whole “Type Manipulation” section of the handbook describing how to carry type information through all kinds of different convolutions. The author seems proud of this capability, claiming “we can express complex operations and values in a succinct, maintainable way” but I got lost. This is information I could not absorb on the first pass and would have to return frequently as reference.

Since the “easy to read” handbook already lost me on several points, I don’t think I’m quite ready to jump into the full language specification just yet. But there was one more item I wanted to look up: class decorators are used in Angular to create every component, and I didn’t quite understand how that worked. TypeScript reference page for decorators called it an experimentational feature of TypeScript that is also a proposal to JavaScript, which means things might change in the future if JavaScript officially adopts decorators in a way incompatible with what TypeScript does today. Oh well, if that happens, I’m confident the TypeScript people are well practiced at dealing with it. In the meantime, I have to devise a plan for my own TypeScript practice.

Notes on Codecademy “Learn TypeScript”

I want to go back and take another look at Angular web application development framework, because I’ve learned a lot about web development since my earlier attempt. But before I do, I want to review TypeScript, which is what Angular uses to tame some of JavaScript’s wild nature. Conveniently, Codecademy has a “Learn TypeScript” course for me to do exactly that.

As its name implies, TypeScript imposes some of the benefits of data type enforcement to JavaScript’s default data type system, where anything can go anywhere. The downside of JavaScript’s flexibility is that it also allowed many bugs to hide until emerging at very inconvenient times. While it’s always possible to move to an entirely different language if type safety is desirable, the beauty of TypeScript is that it maintains full compatibility with JavaScript so we don’t have to leave that ecosystem (JS runtimes, libraries, tools, etc.) to gain benefits of compile-time type checks. TypeScript accomplishes this magic by performing its checks on TypeScript source files. Once everything has been verified to be satisfactory, that source code is translated to standard JavaScript for execution.

But before that compiler runs, TypeScript syntax gives us a lot of tools to organize our code to catch bugs at “compile” time. (More accurately TypeScript-to-JavaScript transpiling time.) There are static code analysis features to find problems. Starting with simple ones like a mistyped variable name would get caught because it has no declared type. We also get (illusions of) features like enum so we can constrain values within a defined valid set.

However, in order to stay compatible with JavaScript, TypeScript couldn’t offer all the rigorousness of a strictly typed language. There are various middle ground features sprinkled throughout so we don’t have to take all-or-nothing. The type guard of “[property] in [object]” aligns with “duck typing” patterns: checks for the method we care about instead of the exact object type or interface. It was also amusing to see support for generics, which is becoming a feature in strictly typed languages but now we have it in TypeScript as well compiling down to “do whatever you want” JavaScript. That leads to things like Index Signatures with no real counterpart in strictly typed languages, and I credit its existence to JavaScript for being weird. I wouldn’t blame everything on JavaScript, though. I sometimes stumble across TypeScript union types, which lets us support a limited set of types. In one practice exercise, we have an array that can be an array of one of two types. I typed TypeA[] | TypeB[] which made sense to my brain, but that was not acceptable. I had to use (TypeA | TypeB)[] and I still don’t understand why.

This course also exposed me to certain JavaScript things that were not specific to TypeScript. There was a brief mention of documentation comments: /** */ blocks that included markup like @param and @returns. I vaguely recall seeing this before but I no longer remember what this is called and the course didn’t give me a pointer. This course was also the first time I saw JavaScript rest parameters and its counterpart spread syntax. And finally, this is where I learned of number.toFixed() which I will definitely use in the future.

Like all Codecademy courses, this one gives us enough context for us to navigate product document on our own. In this case, the official reference is The TypeScript Handbook. Explanations in the handbook make a lot more sense to me after this Codecademy course than it did before, so I’d say “Learn TypeScript” was worth my time investment.

Notes on “Using MongoDB with Node.js” from MongoDB University

Most instructional material (and experimentation) for MongoDB uses the MongoDB Shell (mongosh), which is “a fully functional JavaScript and Node.js 16.x REPL environment for interacting with MongoDB deploymentsaccording to mongosh documentation. Making mongosh the primary command line interface useful for exploration, experimentation, and education like on Codecademy or MongoDB University.

Given the JavaScript focus of MongoDB, I was not surprised there is a set of first-party driver libraries to translate to/from various programming languages. But I was surprised to find that Node.js (JavaScript) was among the list of drivers. If this was all JavaScript anyway, why do we need a driver? The answer is that we don’t use JavaScript to talk to the underlying database. That is the job of BSON, the binary data representation used by MongoDB for internal storage. Compact and machine-friendly, it is also how data is transmitted over the network. Which is why we need a Node.js library to convert from JSON to BSON for data transmission. I started the MongoDB University course “Using MongoDB with Node.js” to learn more about using this library.

It was a short course, as befitting the minimal translation required of this JavaScript-focused database. The first course covered how to connect to a MongoDB instance from our Node.js environment. I decided to do my exercises with a Node.js Docker container.

docker run -it --name node-mongo-lab -v C:\Users\roger\coding\MongoDB\node-mongo-lab:/node-mongo-lab node:lts /bin/sh

The exercise is “Hello World” level, connecting to a MongoDB instance and listing all available databases. Success means we’ve verified all libraries & their dependencies are install correctly, that our MongoDB authentication is set up correctly, and that our networking path is clear. I thought that was a great starting point for more exercises, and was disappointed that we actually didn’t use our own Node.js environment any further in this course. The rest of the course used the Instruqt in-browser environment.

We had a lightning-fast review of MongoDB CRUD Operations and how we would do them with the Node.js driver library. All the commands and parameters are basically identical to what we’ve been doing in mongosh. The difference is that we need an instance of the client library as the starting point, from which we could obtain object representing a database and a collection with it. (client.db([database name]).collection([collection name]) Once we have that reference, everything else looks exactly as they did in mongosh. Except now they are code to be executed by Node.js runtime instead of typed. One effect of running code instead of typing commands is that it’s much easier to ensure transaction sessions complete within 60 seconds.

For me, a great side effect of this course is seeing JavaScript async/await in action doing more sophisticated things than simple straightforward things. The best example came from this code snippet demonstrating MongoDB Aggregation:

    let result = await accountsCollection.aggregate(pipeline)
    for await (const doc of result) {
      console.log(doc)
    }

The first line is straightforward: we run our aggregation pipeline and await its result. That result is an instance of MongoDB cursor which is not the entire collection of results but merely access to a portion of that collection. Cursors allow us to start processing data without having to load everything. This saves memory, bandwidth, and processing overhead. And in order to access bits of that collection, we have this “for await” loop I’ve never seen before. Good to know!

Many Paths to MongoDB Shell (mongosh)

To promote their product, MongoDB has setup their own online learning resource MongoDB University. I was curious to learn more about a database that offers something different from a standard SQL relational database, so I started with their “Introduction to MongoDB” course. Since it was at least partially a marketing tool, I was not surprised the course wanted to take us through a grand tour through all MongoDB products from their cloud-hosted MongoDB Atlas data platform to all the tools we can download and install. I was ready to just ignore and skip over those sales pitches, but then the course would quiz me to make sure I’ve actually installed them on my computer. This annoyed me, especially for the MongoDB Shell (mongosh). It’s how Codecademy introduces us to MongoDB, and it’s what we use in MongoDB University’s Instruqt hands-on labs. There are so many ways to get mongosh I refuse to download and run a full blown application installer package just for a command line tool.

At a minimum, this duplicates work. MongoDB Compass is another item the course wants us to download and install. Compass is a separate application that offers GUI-based methods for interacting with a MongoDB database and/or Atlas cluster. GUI are nice but rarely cover 100% of all scenarios, so developers like the option of dropping to a command line. Which is why clicking at the bottom of MongoDB Compass would bring up an integrated mongosh.

I’ve been using Docker as a tool to avoid installing software directly on my computer. I couldn’t escape installing MongoDB Compass because of its graphics interface, but as a command line tool mongosh is easy to run through Docker. The easiest way is to use the official MongoDB Docker image, which includes mongosh alongside the core database engine.

docker run --rm -it mongo:latest mongosh [connection string]

Doing this means we’re pulling down the entire MongoDB database just for the little mongosh tool. That’s like ordering an entire seven-course meal to eat just the little cherry on top of ice cream dessert. Even in this age of broadband internet, that seems rather excessive. I thought it’d be neat to try setting up a container just for mongosh, see if that’s any smaller.

I found instructions for installing mongosh on an Ubuntu instance. Ubuntu Focal is one of the supported versions so I’ll start there.

> docker run --name mymongosh -it ubuntu:focal

I’ll need some tools not found in this basic Ubuntu container, so I need to populate the package index followed by their installation.

> apt update

> apt install wget gnupg

After that I could follow MongoDB instructions. Slightly modified by removing “sudo” as it was unnecessary: we are running as root in this little world.

> wget -qO - https://www.mongodb.org/static/pgp/server-6.0.asc | apt-key add -

> echo "deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/6.0 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-6.0.list

> apt update

> apt install mongodb-mongosh

And voila! I have a docker container “mymongosh” based on the Ubuntu Focal container. Let me see how big it is:

> docker ps --size
CONTAINER ID   IMAGE          COMMAND   CREATED          STATUS          PORTS     NAMES       SIZE
757519a645f8   ubuntu:focal   "bash"    19 minutes ago   Up 19 minutes             mymongosh   278MB (virtual 351MB)

Wow, getting this far meant pulling 278MB on top of 73MB of Ubuntu Focal. This was far larger than I had hoped. While this size still compared favorably with MongoDB image size of almost 700MB, I don’t think my little experiment was worth the effort.

PS C:\Users\roger\coding\PostgreSQL> docker image ls
REPOSITORY                                                        TAG              IMAGE ID       CREATED         SIZE
mongo                                                             latest           2dd27bb6d3e6   7 days ago      695MB

If I want small size, I’d have to learn how to build a minimal Docker image based on Alpine, which isn’t what I want to focus on right now. My next objective is to learn how to use MongoDB from Node.js code instead of mongosh.

Notes on “Introduction to MongoDB” on MongoDB University

I started learning about MongoDB on Codecademy, but there were technical difficulties blocking my progress. So I switched to MongoDB University, the free online learning platform hosted by MongoDB themselves. There was a bit of a learning curve on idiosyncrasies of MongoDB’s learning platform, but I got the hang of it soon enough and could focus on the information covered by “Introduction to MongoDB” course.

Each section of the course starts with a Wistia-hosted video. I prefer to learn by reading at my own pace over watching a video, so this wasn’t my favorite. The video sometimes has captions allowing us to read along with the spoken narrative, but the presence of captions was inconsistent. Sometimes the video is followed by a page of text covering the same information and I thought I could read that text and skip the video, only to find that sometimes the text is missing information covered by the video and vice versa. I end up having to do both video and repetitive text, which feels like a tremendously inefficient way to do things.

Another inefficiency are the hands-on labs powered by Instruqt. It takes several clicks and a few tens of seconds for the lab environment to spin up, which isn’t bad by itself except most of our exercises involve typing out a single mongosh (MongoDB Shell) command and exiting to proceed to the next lab. This implementation means we spend a lot of time twiddling our thumbs waiting for spin-up and tear-down overhead, I would have preferred that we do more in each Instruqt session, so we don’t spend so much time waiting.

As for the course material, it’s not technically just about the MongoDB database itself, the course is also a sales pitch for associated MongoDB products. Mainly MongoDB Atlas, the cloud-hosted (your choice of AWS, Azure or GCP) MongoDB service that cost money for us and generates revenue for the company. I don’t mind a company making sure we know how to give them money, but I don’t care for the fact that MongoDB Atlas features are intermingled with MongoDB core functionality in this course. When we run our own MongoDB instance (which I plan to do for my own projects) we won’t have Atlas functionality, but this course doesn’t always make clear what is core MongoDB versus functionality added by Atlas. I expect the company would say “Don’t need to bother, just use Atlas for your projects, we have a free tier!” and I appreciate that the offer exists. But I’m rather skeptical that their “Free Forever” tier will actually stay free given the discouraging historical record of free tiers.

Instructions in MongoDB mostly concentrate on what we can type into mongosh, which exposes a JavaScript style interface for interacting with a database. That is very different from storing SQL commands in strings as we did in node-sqlite. Compared to SQL syntax, I found it easier to remember and parse mongosh syntax because of its similarity to JavaScript. That said, I still come across things that feel inconsistent to me that catch me off guard. Some commands want us to specify an action first then where to store the results. {$count: "total_items"} Other commands want us to specify the location of results followed by the action to generate it. {"total_items": {$count {}}} Maybe there’s a system and I just haven’t learned them yet, certainly the course never tried to explain them.

At least I could still follow the logic for most of those inconsistencies. The one that completely confused me was an example using geographical location data in the form of { type: 'Point', coordinates: [ 40, -74 ] } I think this is their GeoJSON format but the course didn’t go into detail. The example then sorted by ‘latitude‘, and I don’t see how I could have looked at ‘type‘ and ‘coordinates‘ and decide ‘latitude‘ is available for sorting. To my eye ‘latitude‘ was not defined at all! If I figure this out later, I’ll add a URL here to the appropriate reference.

Here is my super-abbreviated variation of course syllabus:

  • Querying for data with db.[collection].findOne() and find(). Followed by insert with insertOne() and insertMany(). We start with a few basic query operators using comparison operators $gt, $gte, $lt, and $lte. Then logical operators like $and and $or. We can use $elemMatch if we want to peer into values in the form of an array.
  • Modifying data with replaceOne for direct replacement. updateOne() and updateMany() take operators like $set and $push. findAndModify() combines a common pattern of finding a single document, modifying it, and returning the results. Finally deleteOne() to remove documents.
  • Tailor query results with cursor.sort() and limit(). Projection parameter to find() lets us skip information we’re not interested in. And collection.countDocuments() is useful for data exploration.
  • Aggregation is roughly analogous to SQL table joins. We are introduced to operators $match, $group, $sort, $limit, $project, $count, $set, and $out.
  • Index helps us optimize lookup for specific query patterns. Recommend we list the fields in usage order of Equality, Sort, then Range. (But couse didn’t explain why.) Like SQL, there’s always some tradeoff involved for having a database index. The explain() command helps us see if an index is actually as helpful as expected.
  • There’s a whole arena of information on MongoDB anti-patterns. Like how we should be aware of BSON size limit of 16MB which means avoiding things like creating arrays that would grow unbounded.

This course gave me a solid start to using MongoDB in my projects. As I do not intend to rely on MongoDB Atlas staying free, I’m more likely to run the MongoDB Docker container on a test machine at home. Interactions with such a database would likely happen via mongosh and there are many ways to get it.

Notes on MongoDB University Learning Platform

I’ve been learning a lot of interesting things from Codecademy’s course catalog, including the fundamental concepts of the “NoSQL” database software design of MongoDB. However, when Codecademy’s hands-on learning mechanism got stuck, I couldn’t see how those fundamental concepts translated to MongoDB practice. But that’s OK, the Codecademy MongoDB course was built in conjunction with MongoDB themselves, so I can try their own MongoDB University platform for learning online.

The switch does introduce some friction, though. Starting with the online learning platform itself. Codecademy rarely uses video lectures. (Which I appreciate, and more comments about content will come later.) When they do, they embed a YouTube video and let Google figure out the rest. MongoDB University hosts their (more frequent) video lectures on Wistia. (“Where Video Meets marketing”.) Wistia’s video player component has a slightly different interface from YouTube. The most annoying aspect of the Wistia player is lack of memory across sessions. I prefer playing the videos slightly faster than standard speed, and its lack of memory means I have to click the settings button to speed up playback on Every. Single. Video. I also prefer to turn on English captions, which meant more clicking on every video. Not every MongoDB University video had captions available, but I don’t blame Wistia for that. I do wish they followed YouTube’s lead and offer at least the option of imperfect (but far better than nothing) auto-generated captions.

Since I loved Codecademy giving us hands-on interaction with the material, I was happy to see MongoDB University courses also has a hands-on interaction component powered by Instruqt. (“The #1 Hands-on Virtual IT Labs for Product-led Growth”) For these exercises, Instruqt provides a mongosh (MongoDB interactive shell) command line in our browser window. It feels like they’ve spun up at least two Docker instances for each exercise: one container running mongosh, connected to another container running MongoDB itself. This works well as we get a known starting state for each exercise and, after we’re done, undo anything we’ve changed so the next person gets the same starting state. The downside of a browser-based command line is that we don’t get the full set of command-line keyboard shortcuts. I had to use mouse right-click in order to copy and paste because my preferred keyboard shortcuts didn’t work.

Another similarity to Codecademy are quizzes sprinkled throughout the course to test our comprehension of course material. User interface for these quizzes leave something to be desired. The first problem is when I clicked “Show Results”, I saw items I didn’t select displayed as “Incorrect”. I was confused for a few minutes, reading the explanation trying to figure out where I went wrong. Eventually I figured it out: I wasn’t wrong. They’re just showing me all of the explanations. I did not select the incorrect answer and that was the correct thing to do. That was very confusing. The next problem is literally the “Next” button on these quizzes. After finishing one question, I clicked “Next” to proceed with the quiz, only to get disoriented when the course continued with new material. Eventually I figured out there is a “Next” button to continue with the quiz, and it is near a different “Next” button which will abandon the quiz and proceed with the course. I clicked the latter when I should have clicked the former. This was a pretty bad user interface design but once I figured out what was going on, I could deal with it and focus on the course material.

Notes on Codecademy “Learn MongoDB”

Codecademy’s course catalog on SQL databases is thinner than those on topics like web front-end development, and their in-browser learning infrastructure isn’t as polished for those courses either. This has caused me frustration, but I was still learning useful knowledge. Codecademy’s PostgreSQL skill path was packed with information I can use and links to where I could learn more. After that, though, I wasn’t interested in anything else under their SQL umbrella of courses, but that doesn’t mean I’m done with databases because SQL relational databases are no longer the only game in town: A few alternative “NoSQL” database designs have recently arisen, and I had been curious about their design tradeoffs. So, the next step is Codecademy’s Learn MongoDB course, which I learned was launched (or at least promoted) recently via a Codecademy mailing list. Unfortunately its technical immaturity caused problems, more on that later.

This course started well, with a review of databases for those who come into the course without a background in SQL relational databases. With that background established, it proceeded to describe how NoSQL databases (there are several subtypes) like MongoDB (representing the “document database” subtype) go about their business. I loved this section, because it answered my question about why these databases exist and when they might (or might not!) be the right tool for the job.

On the course syllabus it said “Built in partnership with MongoDB” which in practice meant many links to MongoDB’s established portfolio of guides and documentation. After Codecademy’s own explanation of SQL vs. NoSQL, we have a link to MongoDB’s own take. Related to that topic is a presentation that describes MongoDB structures in terms of close analogues in SQL, but also implored experienced database developers to free their mind and think beyond relational database conventions. It seems perfectly possible to set up a MongoDB database so it looks and act like a relational database, but not taking advantage of MongoDB strengths risks incurring all the disadvantages of NoSQL without any reward to balance them out.

The MongoDB advantage that really caught my attention is the ability to start working on a project before we know everything about data access patterns. In a SQL-backed project that is a recipe for disaster because incomplete information would lead to a suboptimal schema, and one that we’d be stuck with towards the end of the project. Over in MongoDB land, our data validation can be loose in early stages of the project and tightened as we go if desired. During the course of development, MongoDB can theoretically adapt to changes much more easily than SQL databases could handle schema updates. I wonder if this means it’s possible for an application to evolve their MongoDB usage and end up in a state where it’d make sense to migrate to a SQL relational database.

These features were all very promising, and I really looked forward to playing with MongoDB. Unfortunately, Codecademy’s hands-on lesson backend is broken today. On the first page of the first interactive lesson, I was told to show all databases in a MongoDB instance by typing in the “show dbs” command, which listed four databases as expected. After this list was shown, I was to click the “Check Work” button to verify my progress before proceeding. But when I clicked “Check Work”, nothing happened. I did not see a successful check, which would have allowed me to proceed. In the absence of success check, I expect to see a red X telling me my answer was wrong and need to try again. But I didn’t see that, either. Nor did I see any sort of an error message. No “Pass”, no “Fail”, and not even a “Oh no something is wrong”.

I’m stuck.

So Codecademy’s Learn MongoDB course was a bust, but as mentioned earlier, MongoDB has their own collection of learning resources. The reading material so far got me interested enough that I want to continue learning MongoDB. Instead of waiting for Codecademy to fix their backend, I will switch to MongoDB’s learning platform.

[UPDATE: Codecademy has fixed their MongoDB course and I could continue its lesson, which is now extremely easy and just a review as I’ve since gone through courses on MongoDB’s own learning platform.]

Notes on Codecademy “Design Databases with PostgreSQL”

After a frustrating experience with the node-sqlite course on Codecademy, I’ve concluded that their in-browser instruction environment is not well set up for teaching SQL. Or at least, this course is far weaker than others on Codecademy, which I had been generally satisfied up until this point. I considered switching to a different topic but decided there were still a few more things I wanted to learn. But from here on out, when I fail an exercise, I’m more likely to decide my answer was fine. (More willing to hit “View Solution” to see the answer and compare.) And more importantly, I’m going to review the course syllabus beforehand and skip those with frustrating “Code Challenge” sections.

Which led me to “Design Databases with PostgreSQL” which is technically a “Skill Path” offering rather than a course. Like my previous skill path in web development, I started this skill path and was immediately at 50% completion due to material that overlapped with courses I’ve already taken. One major difference is that all my Codecademy database courses used SQLite to illustrate general SQL concepts, but this skill path has some PostgreSQL-specific details amongst more general database concepts.

Initially, I was mildly disappointed that the material was shallower than I had expected based on course description. The sales pitch made it sound like we’re going to get into some real detailed nuts-and-bolts, but while the course did indeed to into further depth than other courses to date, there were still many topics that ended with “we’re not going into more depth, but at least now you are aware it exists.” An example concerns database keys. From my earlier courses I had known about primary, foreign, and composite keys. This course mentioned there are also super, candidate, and secondary keys then proceeded to say nothing more about them. As a starting pointer this is fine, I had just expected more.

Once I adjusted my expectations, this skill path was time well spent. We get more information on database schema and that proper design of a schema can make a difference in database performance. Both at development time (make queries easier and less prone to problems) and at runtime (easier updates and faster queries.) Part of this design process is database normalization, which was covered by starting with a poorly designed database. After covering how a poorly normalized database causes problems in use, we are walked through typical normalization techniques to solve those problems.

But those solutions usually have a tradeoff. This course has a recurring theme in the form of database tradeoffs. A competent database engineer has to be able to understand the problem domain and usage patterns to properly prioritize certain constraints versus others. A normalized database has a lot of space, performance, and consistency advantages. But it does tend to make updates and queries more complex by requiring database joins. Similarly, a database index can make queries faster, but maintenance means updates are slower. The index also takes up space on disk.

A light complaint I have about this course is that its illustrative examples were surprisingly poor. One example used an email address as a primary key for a list of people, but a person can have multiple email addresses making it a poor primary key. Another example separated ingredients from recipes, but the ingredient is associated with a fixed amount. It is unrealistic for a cookbook to use, say, the same amount of salt for every recipe.

One of the practice exercises was “Bytes of China”, setting up a database that would track information suitable for a restaurant menu. From the starting directions I had looked forward to an open-ended exercise, because it said to: “Create table with columns that make sense based on the description” This came to a screeching halt when we were given information to add to these tables in the form of SQL INSERT clauses that expect a specific database schema. I had to delete the database schema that made sense to me and rebuild a different schema to suit the exercise data. This was annoying. They could have told us to build to suit their sample data upfront instead of letting us waste time designing our own that wouldn’t work.

Gripes aside, I learned a lot of neat things that I expect to use in future projects that might need a database. I learned how it was possible to represent many-to-many relationships with a “join table” that has a composite primary key that consists of a combination of foreign keys. Beyond “PRIMARY KEY” I learned about constraints like UNIQUE, CHECK, and REFERENCES. In the earlier SQLite course I was dismayed to learn it doesn’t enforce the schema, calling it a flexible feature instead of a bug. PostgreSQL isn’t as free-wheeling but we still need to watch out for times when it becomes inadvertently unhelpful. If I make a mistake trying to put a floating-point number like 1.5 into an integer field, PostgreSQL would round it to 2 without error. Or if I make a mistake putting it into a text field, PostSQL would helpfully convert the number 1.5 to the string “1.5”.

Every bit of SQL instruction I’ve come across before only ever joined two tables, this course was the first to teach me how to join more than two. I can see how this would feel obvious to SQL veterans, but every beginner has to see it at least once:

SELECT table_one.column_one AS alias_one, table_two.column_two AS alias_two, table_three.column_three AS alias_three
FROM table_one
INNER JOIN table_two
ON table_one.primary_key = table_two.foreign_key
INNER JOIN table_three
ON table_two.primary_key = table_three.foreign_key;

I think all of the remaining nifty tricks are PostgreSQL-only, but I’m not sure. The course doesn’t make a lot of distinction between thing we can use in other databases versus PostgreSQL-only. So I don’t know if I can extract just the date from a timestamp (DATE_PART()) with other databases, or if I can make this query to examine constraints on record for a table:

SELECT
  constraint_name, table_name, column_name
FROM
  information_schema.key_column_usage
WHERE
  table_name = 'fill in table name';

Given the pg_ prefix, the following query is likely PostgreSQL specific way to list every index built for a table.

SELECT *
FROM pg_Indexes
WHERE tablename = 'fill in table name';

Also with the prefix is a query to show size of a table, which includes space consumed by storing data and all associated index.

SELECT pg_size_pretty (pg_total_relation_size('products'));

And finally, we get a few starting points for performance analysis. Like prepending EXPLAIN ANALYZE in front of a query to get information on how the database plans out its execution. Or SELECT NOW(); to print out a timestamp before and after an operation so we can see how long it took.

That’s a lot of information packed into a single Skill Path. I wished for more, but I can understand there’s a tradeoff against making the course too long. Maybe this is the perfect length after all, and just enough for me to learn more on my own later. I can spend years learning all the intricacies of relational databases, but right now I’m more curious to explore something a little different.

Notes on Codecademy “Learn Node-SQLite”

After my SQL fresher course, shortly after learning Node.js, I thought the natural progression was to put them together with Codecademy’s “Learn Node-SQLite” course. The name node-sqlite3 is not a mathematical subtraction but that of a specific JavaScript library bridging worlds of JavaScript and SQL. This course was a frustrating disappointment. (Details below) In hindsight, I think I would have been better off skipping this course and learn the library outside of Codecademy.

About the library: Our database instructions such as queries must be valid SQL commands stored as strings in JavaScript source code. We have the option of putting some parameters into those strings in JavaScript fashion, but the SQL commands are mostly string literals. Results of queries are returned to the caller using Node’s error-first asynchronous callback function convention, and query results are accessible as JavaScript objects. Most of library functionality are concentrated in just a few methods, with details available from API documentation.

This Codecademy course is fairly straightforward, covering the basics of usage so we can get started and explore further on our own. I was amused that some of the examples were simple to the point of duplicating SQL functionality. Specifically the example for db.each() shows how we can tally values from a query which meant we ended up writing a lot of code just to duplicate SQL’s SUM() function. But it’s just an example, so understandable.

The course is succinct to the point of occasionally missing critical information. Specifically, the section about db.run() say “Add a function callback with a single argument and leave it empty for now. Make sure that this function is not an arrow.” but didn’t say why our callback function must not use arrow syntax. This minor omission became a bigger problem when we roll into the after-class quiz, which asked why it must not use arrow syntax. Well, you didn’t tell me! A little independent research found the answer: arrow notation functions have a different behavior around the “this” object than other function notations. And for db.run(), our feedback is stored in properties like this.lastID which would not be accessible in an arrow syntax function. Despite such little problems, the instruction portion of the course were mostly fine. Which brings us to the bad news…

The Code Challenge section is a disaster.

It suffers from the same problem I had with Code Challenge section of the Learn Express course: lack of feedback on failures. Our code was executed using some behind-the-scenes mechanism, which meant we couldn’t see our console.log() output. And unlike the Learn Express course, I couldn’t workaround this limitation by throwing exceptions. No console logs, no exceptions, we don’t even get to see syntax errors! The only feedback we receive is always the same “You did it wrong” message no matter the actual cause.

Hall of Shame Runner-Up: No JavaScript feedback. When I make a JavaScript syntax error, the syntax error message was not shown. Instead, I was told “Did you execute the correct SQL query?” so I wasted time looking at the wrong thing.

Hall of Shame Bronze Medal: No SQL feedback. When I make a SQL command error, I want to see the error message given to our callback function. But console.log(error) output is not shown, so I was stabbing in the dark. For Code Challenge #13, my mistake was querying from “Bridges” table when the sample database table is actually singular “Bridge”. If I could log the error, I would have seen “No such table Bridges” which would have been much more helpful than the vague “Is your query correct?” feedback.

Hall of Shame Silver Medal: Incomplete Instructions. Challenge #14 asked us to build a query where “month is the current month”. I used “month=11” and got nothing. The database had months in words, so I actually needed to use “month=’November'”. I wasted time trying to diagnose this problem because I couldn’t run a “SELECT * FROM Table” to see what the data looked like.

Hall of Shame Gold Medal Grand Prize Winner: Challenge #12 asks us to write a function. My function was not accepted because I did not declare it using the same JavaScript function syntax used in the solution. Instructions said nothing about which function syntax to use. After I clicked “View Solution” and saw what the problem was (image above) I got so angry at the time it wasted, I had to step away for a few hours before I could resume. This was bullshit.


These Hall of Shame (dis)honorees almost turned me off of Codecademy entirely, but after a few days away to calm down, I returned to learn what Codecademy has to teach about PostgreSQL

Notes on Codecademy “Learn SQL”

I’m a little sad that hobbyist web app projects have lost the option of free hosting on Heroku, but that’s no reason to stop learning. Heroku is not irreplaceable, I’m sure I can figure out something if a project proceeds far enough to be worth the effort. So, back to learning: where should I go next? Looking at project ideas that involve Node.js and potentially Express, I decided the next area of focus is a backing datastore. It’s time for some database refresher work starting with Codecademy’s “Learn SQL“.

I’ve taken several database courses in the past, to varying levels of rigor and depth. I expected the introductory material of this course to be review so I’m better able to learn new concepts later in the course. As it turned out, this course was entirely review for me but to be fair, some concepts were fresher in my mind than others. I especially appreciated the cool animations illustrating various table joins.

This specific course could be more accurately titled “Learn SQLite” because that’s the database engine used in the course. Which is fine, it covers all the basics. The one thing I hadn’t known (or had forgotten) about SQLite is its… flexibility… in data types. It is standard operating procedure for SQL tables to be declared with a data schema. “Names are strings, IDs are numbers”, etc. While SQL was designed for the database engine to enforce this schema, SQLite does not. When the Codecademy course mentioned this, I said “What!?” but the assertion checks out, confirmed by SQLite’s own FAQ which declares type flexibility as a feature and not a bug. I come from a world of strictly typed programming languages like C, so flexible typing like JavaScript feels more like a problem waiting to happen than a feature. I feel the same with SQLite’s lack of schema enforcement.

Another reason to take a SQL refresher course now is to review all concepts from a new perspective. Now that I am thinking of using a database as backend storage for a web application. From this perspective, some of SQL features make less sense than in other contexts. For example, I’m not sure ORDER BY makes sense to do within the database engine, as a web app almost certainly needs to have sorting logic anyway. Think of the shopping sites that lets the user reorder by availability, by lowest price, etc. For small datasets I’d want to do that on the client end instead of round-tripping each new sort as a new query all the way to the database. But the story changes for large datasets. It’ll make sense to sort data on the database if we want things ordered and then LIMIT to the top X items. That reduces bandwidth consumption between server and client and would be a good tool to have.

In contrast, other features like CASE (to categorize values), AS (to rename columns), and ROUND (rounding numbers) are definitely tasks better performed on the client end. I can’t think of a scenario (yet) where it makes sense to do that work on the server-side database.

This course touches on the concepts of primary keys and foreign keys, but other than uniqueness we didn’t get any further details of relational database design. This course didn’t cover concerns of properly designing a database to suit the task, such as database normalization. As a result, this course is good for setting someone up to use an existing database, but not enough to help them set up a new database. Or at least, not an efficient or effective one. Maybe that’ll be part of another course.

Notes on Codecademy “Learn Express”

I may have my quibbles with Codecademy’s Learn Node.js course, but it at least gave me a better understanding to supplement what I had learned bumping around on my own. But the power of Node isn’t just the runtime, it’s the software ecosystem which has grown up around it. I have many many choices of what to learn from this point, and I decided to try the Learn Express course.

Before I started the course, I understood Express was one of the earlier Node.js frameworks for building back end of websites in JavaScript. And while there have been many others that have come online since, with more features and capabilities, Express is still popular because it set out not to pack itself with features and capabilities. This meant if we wanted to prototype something slightly off the beaten path, Express would not get in our way. This sounded like a good tool to have in the toolbox.

After taking the course, I learned how Express accomplishes those goals. Express Routes helps us map HTTP methods (GET/POST/PUT/DELETE) to JavaScript code via “Routes”, and for each route we can compose multiple JavaScript modules in the form of “Middleware”. With this mechanism we can assemble arbitrary web API by chaining middleware modules like LEGO pieces to respond to HTTP methods. And… that’s basically the entirety of core Express. Everything else is optional, so we only need to pull in what we need (in the form of middlware modules) for a particular project.

When introducing Routes in Express, our little learning JavaScript handler functions are actually fully qualified Middleware, but we didn’t know it yet. What I did notice is that it had the signature of three parameters: (request, response, next). The Routes course talked about reading request to build our response, but it never talked about next. Students who are curious about them and striking out to search on their own as I did would find information about “chaining”, but it wouldn’t make sense until we learned Middleware. I thought it would have been nice if the course would say “we’ll learn about next later, when we learn about Middleware” or something to that effect.

My gripe with this course is in its quiz sections. We are given partial chunk of JavaScript and told to fill in certain things. When we click “Check Work” we trigger some validation code to see if we did it right. If we did it wrong, we might get an error message to help us on our way. But sometimes the only feedback we receive is that our answer is incorrect, with no further feedback. Unlike earlier Node course exercises, we were not given a command prompt to run “node app.js” and see our output. This meant we could not see the test input, we could not see our program’s behavior, and we could not debug with console.log(). I tried to spin up my own Node.js Docker container to try running the sample code, but we weren’t given entire programs to run and we weren’t given the test input so that was a bust.

I eventually found a workaround: use exceptions. Instead of console.log('debug message') I could use throw Error('debug message') and that would show up on the Codecademy UI. This is far less than ideal.

Once I got past the Route section, I proceeded to Middleware. Most of this unit was focused on showing us how various Middleware mechanisms allow us to reduce code duplication. My gripe with this section is that the course made us do useless repetitive work before telling us to replace them with much more elegant Middleware modules. I understand this is how the course author chose to make their point, but I’m grumpy at useless make-work that I would delete a few minutes later.

By the end of the course, we know Express basics of Route and Middleware and got a little bit of practice building routes from freely available middleware modules. The course ends by telling us there are a lot of Express middleware out there. I decided to look into Express documentation for some starting points.

Notes on Codecademy “Learn Node.js”

I’ve taken most of Codecademy’s HTML/CSS course catalog for front-end web development, ending with a series of very educational exercises created outside of Codecademy’s learning environment. I think I’m pretty well set up to execute web browser client-side portions of my project ideas, but I also need to get some education on server-side coding before I can put all the pieces together. I’ve played with Node.js earlier, but I’m far from an expert. It should be helpful to get a more formalized introduction via Codecademy, starting with Learn Node.js.

This course recommends going through Introduction to JavaScript as a prerequisite, so the course assumes we already know those basics. The course does not place the same requirement on Intermediate JavaScript, so some of the relevant course material is pulled into this Node.js course. Section on Node modules were reruns for me, but here it’s augmented with additional details and a pointer to official documentation.

The good news for the overlap portions is that it meant I already had partial credit for Learn Node.js as soon as I started, the bad news is the Codecademy’s own back-end got a little confused. I clicked through “Next” for a quick review, and by doing so it skipped me over a few lessons that I had not yet seen. My first hint something was wrong was getting tossed into a progress checking quiz and being baffled: “I don’t remember seeing this material before!” I went back to examine the course syllabus, where I saw the skipped portions. The quiz was much easier once I went through that material!

This course taught me about error-first callback functions, something that is apparently an old convention for asynchronous JavaScript (or just Node) code that I hadn’t been aware of. I think I stumbled across this in my earlier experiments and struggled to use the effectively. Here I learn they were the conceptual predecessor to promises, which led to async/await which plays nice with promises. But what about even older error-first callback code? This is where util.promisify() comes into the picture, so that everyone can work together. Recognizing what error-first callbacks are and knowing how to interoperate via util.promisify(), should be very useful.

The course instructs us on how to install Node.js locally on our development computers, but I’m going to stick with using Docker containers. Doing so would be inconvenient if I wanted to rely on globally installed libraries, but I want to avoid global installations as much as possible anyway. NPM is perfectly happy to work at project scope and that just takes mapping my project directory as a volume into the Docker container.

After all, I did that as a Docker & Node test run with ESP32 Sawppy’s web interface. But that brought in some NPM headaches: I was perpetually triggering GitHub dependabot warnings about security vulnerabilities in NPM modules I hadn’t even realized I was using. Doing a straight “update to latest” did not resolve these issues, I eventually figured out it was because I had been using node-static to serve static pages in my projects. But the node-static package hadn’t been updated in years and so it certainly wouldn’t have picked up security fixes. Perhaps I could switch it to another static server NPM module like http-server, or get rid of that altogether and keep using nginx as sheer overkill static web server.

Before I decide, though, this Learn Node.js course ended with a few exercises building our own HTTP server using Node libraries. These were a little more challenging than typical Codecademy in-course exercises. One factor is that the instructions told us to do a lot of things with no way to incrementally test them as we go. We didn’t fire it up the server to listen for traffic (server.listen()) until the second-from-final step, and by then I had accumulated a lot of mistakes that took time to untangle from the rest of the code. The second factor is that the instructions were more vague than usual. Some Codecademy exercises tell us exactly what to type and on which line, and I think that didn’t leave enough room for us to figure things out for ourselves and learn. This exercise would sometimes tell us “fill in the request header” without details or even which Node.js API to use. We had to figure it all out ourselves. I realize this is a delicate balance when writing course material. I feel Codecademy is usually too much “do exactly this” for my taste, but the final project of Learn Node.js might have gone too far in the “left us flailing uselessly” direction.

In the meantime, I believe I have enough of a start to continue learning about server-side JavaScript. My next step is to learn Express.

Notes on Codecademy “Build a Website” Off-Platform Projects

Most Codecademy courses involve interactive learning inside their in-browser learning development environment, but occasionally we are directed to get off Codecademy platform and build something on our own. I have set up nginx as a local development web host (not the best use of nginx) serving files directly off a GitHub repository for these projects. This repository is, in turn, set up to host project content via GitHub pages. After this infrastructure is setup, I dove in to the off-platform project assignments of Built a Website with HTML, CSS, and Github Pages skill path.

The first project was “Dasmoto’s Arts & Crafts”, a relatively simple art shop landing page exercising a beginner’s level of HTML and CSS. We are given the images to use, and a specification of how the site should look. This was a practice exercise intended for us to run directly off local filesystem, without even a web server. But where’s the fun in that? I built this project locally, serving my files via nginx.

The next project was “Tea Cozy”, a more sophisticated tea shop landing page. This was from “Flexbox and Grid” section that pulled in most of the material of Learn CSS: Flexbox and Grid. Again, we are given a set of images to use, and a specification for how the site should look. This layout is far more complex than “Dasmoto’s Arts & Crafts” project, requiring use of (no surprise) flexbox and grid. I enjoyed the challenge of building “Tea Cozy” and I feel I have a much better grasp of flexbox & grid after this project.

Towards the end of the skill path was a project “Excursion”, a coming-soon phone app landing page. In addition to the images, we also had a video to embed. I had thought it be more of a skill practice than “Tea Cozy”, but it turned out to be far simpler with minimal layout challenges. The focus of this exercise was on GitHub Pages, a topic I had already put in the time to learn, so I blitzed through it relatively quickly. My only problem was trying to incorporate the copyright symbol, which wasn’t as simple as copy and pasting the Unicode character. A strange character gets added whenever I try to do so! I decided this problem wasn’t technically a HTML/CSS issue and punted.

And finally, we have a capstone project “Colmar Academy” educational institution landing page. We have a lot of added complexity in this project. This is the first project to require responsive layout, with both desktop and mobile views required. Some of the images provided had corresponding high-resolution desktop and low-resolution mobile versions. There was a video, and we even get a few icons in the form of SVG files. The specification we were given for this project was more loosely defined, with fewer explicit details, and we are to use our design sense to fill in the gaps. For example, it was up to us to decide where our media query breakpoints would be to transition between desktop and mobile views. This project took a lot of time, but it was time well spent because of everything I learned while doing it. At the moment, my biggest unsolved mystery is how to switch between desktop and mobile images from CSS. I couldn’t change the value of src property on an <img> tag from CSS! I ended up using two <img> tags, one with the desktop image and one with the mobile image and using CSS media query to set one of them to display: none; This feels inelegant, and I hope I learn a better way to do this in the future.


My code for these assignments are publicly visible on GitHub.

Notes on Codecademy “Build a Website with HTML, CSS, and Github Pages” Skill Path

After finishing Codecademy’s navigation design course, I thought it had some interesting information but it also spent too much time on CSS tricks I did not expect to be broadly applicable to future projects. Completing that course also meant I had covered majority of Codecademy’s courses under HTML & CSS section of the catalog. However, there are a few items listed that were not “Courses” so I thought I would check out a “Skill Path”. According to Codecademy, a skill path is focused on delivering the knowledge necessary to accomplish certain tasks. I paraphrase it as “Teach me what I need to know to accomplish X” versus a course which is more “Tell me about Y and how I might use it.”

In practice, judging by my first skill path “Build a Website with HTML, CSS, and Github Pages” (Or the shorter “Learn How to Build Websites” as per the URL) a skill path repackages a lot of components pulled from other Codecademy resources. Mostly individual lessons (modules?) but also other resources like their articles and blogs. After taking majority of Codecademy courses on HTML/CSS, going through this skill path was a little disorienting because their backend had tracked which modules I’ve already done. This meant that as soon as I clicked on starting this skill path, my progress was immediately over 50% complete. Looking over the skill path syllabus, I could see what I’ve already done and the gaps I still need to cover.

Most of the gaps were information presented Codecademy articles, covering things like how to set up a code editor like Visual Studio Code. (My personal choice.) Some of the gaps were modules on courses I hadn’t bothered to take, for example the command line course as I was already quite comfortable, but I was able to blitz through quickly.

A surprise was the gap on web accessibility. I thought this was an error as I had taken their Learn CSS Accessibility course, but the database is correct: this was a different course with material I had wished was in the CSS accessibility course. Starting with basic background and on to how to set up a screen reader for us to explore how these features will be consumed. I also appreciated more information on ARIA roles, where I learned we can put down some very fine-grained annotations for accessibility. There are a lot more ARIA roles than there are semantic HTML elements. It’ll take a lot of learning and practice to do ARIA well, but if the spec is too overwhelming, we can start with MDN’s introduction to ARIA.

I was heartened by this coverage of web accessibility but was then disappointed by its coverage of Font Awesome. Which I learned is a huge collection of icons (apparently not fonts as the name implies) available for use in websites. Icons are inherently compact way of visual communication, so we need to pay more attention to their use to ensure they are accessible. Unfortunately, not only did the course not cover how to maintain accessibility, it does not even mention accessibility as a concern when using icons.

One section I’m glad they put in this course is “Documentation and Research”. There’s no way for the course to cover everything, so it needs to teach people how to look stuff up on their own. For web developers, this means the holy trinity of MDN, Google, and StackOverflow. And for beginners who needed the exercise, a broken web site to fix by looking up the problems.

The real star of the skill path, though, are the off-platform projects. I like learning with Codecademy and its embedded interactive development environment. We can get a lesson side by side with sample code we can play with. However, these are all fairly basic fill-in-the-blank types of exercises. To be a web developer we need to be able to build a page from scratch, which is where these off-platform projects come in. We are given the assets (images and occasionally video) and a specification of what to build, but no templates. We had to create our own index.html and style.css from scratch and serve it up to in a browser to see our results. This course covered developing on the local file system, and using GitHub Pages, but I decided to add one more option to the mix: I thought it’d be a good exercise to setup nginx for local development hosting.

Notes on Codecademy “Learn Navigation Design”

I was definitely out of my depth with Codecademy’s color design course, but I was happy to absorb what I can and move on to another topic of novelty: Codecademy’s “Learn Navigation Design” course. Just as color could give subtle hints to the user on how to best interact with the site, so does applying good design to navigation elements. It’s something that we would rarely consciously notice until we encounter a poorly designed page, which is of course how this course started: by showing us an intentionally badly designed page and go up from there.

I was surprised that the first topic was how to show links on a page. After all the link styling in previous CSS courses and speaking of the user agent (browser default) stylesheet as a source of problems, this course presents the other side of the story: Hang on, guys, there are good reason they’re the way they are! And if we arbitrarily toss out all of those traits, site usability will suffer. Hover states are discussed here, and this time we’re reminded of their absence on touchscreen devices. We also get a link to MDN on pseudo-classes, information missing from the color design course!

Moving on from links to buttons, it started with an explanation of skeuomorphism vs. flat design for user interactive elements like buttons. This course covers examples for both styles. I’m personally a fan of the flat school of design. If somebody wants to do skeuomorphism on a button, I demand that they look like keys on an IBM Selectric typewriter.

After buttons the course talked about secondary navigation in the form of breadcrumbs on the page, usually found at the top of a site just before the header block. I appreciate an overview of the concept, but some of the examples get into fancy CSS tricks. I don’t think they’ll be generally applicable to all sites and I’m wary they degrade a page’s accessibility.

This navigation design course barely scratched the surface of User Experience (UX) design, but of course there’s an entirely separate Codecademy course “Introduction to UI and UX Design“. Looking over its syllabus, it doesn’t feel like the material would be useful in my personal tinkering projects. There’s also the fact that course was “Built in partnership with Figma” and the final section of the course is “Prototyping with Figma.” Is this course just an extended ad for Figma? I don’t know and at the moment I’m not terribly interested in finding out. At least Figma offers a free starter tier, if I decide to come back to this later.

Right now, I’m more curious about checking out Codecademy’s “Skill Path” offerings.

Notes on Codecademy “Learn Color Design”

After a brief overview of CSS browser compatibility concerns, which wrapped up Codecademy’s Learn Intermediate CSS curriculum, I looked at what remained under Codecademy’s HTML/CSS umbrella and started their Learn Color Design course. This is a less technical course more focused on art & design perspectives, so I knew it would take more effort for me to grasp all the concepts.

At least they started easy (for me) by going over HSL versus RGB for specifying color, and how HSL is easier to work with from a color design perspective. This is something I had learned from working with Pixelblaze and most of the concepts transfer easily. But then we moved quickly into concepts I had never encountered before, like designing color schemes. I liked the fact that the course material stayed with a same example page and changed colors around to illustrate monochromatic, complementary, analogous, and triadic color schemes. Keeping the content identical and changing just the color did help me see the effect somewhat, even if I am not familiar with the kind of vocabulary used. For example, I don’t know what it means for a color scheme to “create a sense of equality, vibrancy, and security in your designs”. These “Color Psychology” concepts are very foreign to my brain and will take time to absorb. Some of the vocabulary is new to me, too, using familiar words in unfamiliar ways. There was a quiz question “How is a shade of a color produced” and none of the possible answers made sense to my brain until I returned to course material and reviewed how the vocabulary is defined in this specific context.

This course had a gem of a quote that I wished more web designers took to heart:

Remember that most users skim websites! They are not reading every word and checking every menu—you need to guide the user to the most important content with good color choices.

Like the lecture, the practice exercise gave us a site that was mostly grayscale and had us add color to it. The instruction ends with an encouraging “Now our site is looking great!” but it really doesn’t. I have yet to master the subtleties in choosing colors and to compensate I intend to use color schemes built by others as much as I could. But this course gave me some foundation so I could appreciate those prebuilt color schemes. It also helped me appreciate BrandColors, a collection of color schemes associated with many brands we see in our everyday lives.

There was an optional resource that pointed to Adobe Color with the claim “you will learn to use Adobe Color” but when clicking the link, I was redirected straight to the color wheel tool. It’s not immediately obvious where I could find anything instructional to help me learn, I think that URL might be outdated. The same “dropped into a tool with no instructions” problem applied to another optional resource, a color tool by CloudFlare Design. (Not to be confused with the CloudFlare that handles DDoS attacks.)

After some experimentation with color, we are to put that theory into practice by applying color for UI. Again, the instruction materials used a sample page that started out mostly grayscale and we added colors as we go. UI-specific concepts are added, such as using colors for button hover and disabled states. An aside: I wish this class discussed the fact that hover is absent from touchscreens and how design should change in response. And speaking of wishes, an earlier wish was granted here: we finally have a discussion on color blindness and given ColorSafe as a tool to help. Another realization I had during this course is that we never really had a discussion on CSS pseudo-classes, which we use to style things like hover states. A quick web search found this MDN resource as a starting point for later research. For now, I will proceed to the navigation design course.