See World(s) Online

NASALogoOne of the longest tenure items on my “To-Do” exploration is to get the hang of the Google Earth API and learn how to create a web app around it. This was very exciting web technology when Google seemed to be moving Google Earth from a standalone application to a web-based solution. Unfortunately its web architecture was based around browser plug-ins which eventually lead to its death.

It made sense for Google Earth functionality to be folded into Google Maps, but that seemed to be a slow process of assimilation. It never occurred to me that there are other alternatives out there until I stumbled across a talk about NASA’s World Wind project. (A hands-on activity, too, with a sample project to play with.) The “Web World Wind” component of the project is a WebGL library for geo-spatial applications, which makes me excited about its potential for fun projects.

The Java edition of World Wind has (or at least used to) have functionality beyond our planet Earth. There were ways to have it display data sets from our moon or from Mars. Sadly the web edition has yet to pick up that functionality.

JPL does currently expose a lot of Mars information in a web-browser accessible form on the Mars Trek site. According to the speaker of my talk, it was not built on World Wind. He believes it was built on Cesium, another WebGL library for global data visualization.

I thought there was only Google Earth, and now I know there are at least two other alternatives. Happiness.

The speaker of the talk is currently working in the JPL Ops Lab on the OnSight project, helping planetary scientists collaborate on Mars research using Microsoft’s Hololens for virtual presence on Mars. That sounds like an awesome job.

Simple Online Digital Photo Frame

The CarrierWave Playground project was created for experimentation with image upload. As intended, it helped me learn things about CarrierWave such as creating versions of the image scaled to different resolutions and extracting EXIF image metadata.

Obviously the image has to be displayed to prove that the upload was successful. I hadn’t intended to spend much time on the display side of things, but I started playing with the HTML and kept going. Logic was added for the browser to report its window size so the optimal image could be sent and scaled to fit. I had a button to reload the page, and it was fairly simple to change it from “reload the current page” to “navigate to another page”. Adding a JavaScript timer to execute this navigation… and voila! I had myself a rudimentary digital photo frame web app that loads and displays image in a sequence.

It’s fun but fairly crude. Brainstorming the possibilities, I imagine the following stages of sophistication:

Stage 1 – Basic: Where I am now, simple JavaScript that performs page navigation on a timer.

Problem: page blinks and abruptly shifts as new page is loaded. To avoid the abrupt shift, we have to eliminate the page switch.

Stage 2 – Add AJAX: Instead of a page navigation, perform a XMLHttpRequest to the server asking for information on the next image. Load the image in the background, and once complete, perform a smooth transition (fade out/fade in/etc.) from one image to the next.

Problem: Visual experience is at the mercy of the web browser, which probably has an address bar and other UI on screen. Also, the user’s screen will quickly go dark due to power saving features. To reliably solve both, I will need app-level access.

Stage 3 – Vendor-specific wrapper: Every OS platform has a way to allow web site authors an express lane into the app world. Microsoft offers the Windows App Studio. Apple has iOS web applications. Google has Android Web Apps.

Unknown: The JavaScript timer is a polling model, do we gain anything by moving to a server-push model? If so, that means…

Stage 4 – WebSocket: Photo updates are triggered by the server. Since I’m on Rails, the most obvious answer is to do this via WebSockets using Action Cable.

Looking at the list, I think I can tackle Stage 2 pretty soon if not immediately.

Stages 3 and 4 are more advanced and I’ll hold off for later.

Neural network in JavaScript

When I was first introduced to neural networks, they were considered algorithms with extremely expensive computational requirements. Even the most trivial network required a high-end PC with lots of memory and floating-point math capability.

Of course, at the time a high-end PC processor ran at 90 megahertz, 32 megabytes of RAM is considered a lot, and floating point math required a separate (and expensive) floating-point co-processor.

Now the cell phones we have in our pockets have faster processor and more memory than those powerful PCs of old. Every current processor has floating-point math capability, no extra chip required.

Which means what used to be the domain of specialized programmers, running on expensive hardware, is now possible everywhere: running in a web browser like the TensorFlow playground.

But it’s still hard for a human to grasp what’s going on inside a neural network as it learns and adjusts. While the accessibility of the technology (meaning how easy it is to obtain) has improved, the accessibility of the knowledge (meaning how easy it is to understand) hasn’t.

Computer brains have made great advances in the past years…

Human brains have not.

A quick look at Phaser

In a quest for something more substantial, I looked into the HTML5 game engine Phaser. It has a large audience and an impressive set of features. It was fun poking through some of the source to see how it does its magic, but I ultimately decided against making my own Phaser creation because it is at its core a bitmap-based system.

Bitmaps don’t scale as nicely as vectors by their nature, and I place a great deal of importance on ability to scale well. In the modern HTML world, the customer might be running resolutions ranging anywhere from a 320 x 480 iPhone screen to a 3840 x 2160 4K desktop display.

The people behind Phaser isn’t blind to this. Part of the core features includes a ScaleManager class to help the process. There are also ways to load lower- or higher-resolution assets in response to the screen resolution used by the particular user. But it is an imperfect solution, there are still bitmap scaling artifacts around that plainly wouldn’t be an issue at all had the system been based on vector graphics.

Most of the Phaser titles don’t bother with scaling at all, or only scale across a few fixed resolutions. I find myself quite annoyed when I load up a sample app, just to see it take up a tiny 320×480 (resolution of the original iPhone) section of my desktop browser.


I’ll keep looking.

Upsetting the NPM apple cart

Decades-old words of wisdom from a computer science pioneer, proven true once again.

A distributed system is one in which the failure of a computer you didn’t even know existed can render your own computer unusable.

Leslie Lamport

In a coincidence of perfect timing, my education of NPM yesterday came just in time for me to understand the left-pad incident. The short version is simple enough to understand: unhappy programmer took his ball and went home, causing a lot of other people grief in the process. The bigger picture, though, needed a bit more knowledge to understand.

While going through the NPM workshop I had noticed a few things. The workshop used a dummy placeholder registry but there was really no technical or policy reason why every Jane and Jack can’t run the same lesson against the global registry. Up to and including the fact that they can clean up (un-publish) their NPM package when the workshop is over.

I found that fact curious. Such open accessibility felt fragile and I was wondering about the mechanisms to make sure the mechanism is fortified against accidents or abuse. It wouldn’t be something covered in a workshop, so I thought I’d see more details of this protection elsewhere.

Nope, I was wrong.

The left-pad story proved that there wasn’t any mechanism in place at all. A hilariously trivial package was yanked, causing many houses of cards to fall down.

For all the wonders of NPM, there are downsides that had its share of critics. This incident kicked the criticism into high gear. The NPM registry owner received a lot of fire from all sides and have pledged to update their procedure to avoid a repeat in the future. But I’m not sure that’s enough for the famously anti-authoritarian OSS purists. For every “conflict resolution policy” there will be some who see “ruling with an iron fist.”


NodeSchool “How to npm” notes

The lesson of the day is “You get what you pay for.”’s workshop to teach NPM (Node.js Package Manager) is titled “How to npm.”  It has the intention of letting students create a package, set up the proper dependency links, publish it, then publish it again to practice sending out updates. Since it would be bad to pollute the global package registry with a bunch of dummy student test packages, the workshop steps publish against a practice registry running locally instead of the real thing.

As of today, there’s a problem with the practice registry. It can accept updates to packages and track the version numbers, but the portion that tracks labels for these versions (“dist-tag” in NPM lingo) is broken and halts the lesson flow with a HTTP 404 error.

The symptoms match a bug in the workshop that was acknowledged, analyzed, and purportedly fixed. However, the fix is incomplete because some people are still seeing the same error in the updated version of the workshop.

Including myself!

I tried to look at the code behind the lesson and try to see if I can come up with a fix for the bug, maybe this can be my first open source contribution! But alas, I’m not yet good enough with Node.js programming to understand what’s going wrong.

Fortunately I’ve already learned a few useful things before I hit this roadblock. I believe all the material useful to somebody consuming packages has been covered. And I don’t expect to publish any packages myself soon.

But if I do, I’ll come back to this workshop again before I commit. Maybe it’ll be fixed by then.

NodeSchool “learnyounode” notes

After making my first pass through the jQuery Learning Center (I’m sure I’ll be back again) I moved on to another free learning resource: NodeSchool is a collection of resources for learning Node.js, including some self-training tutorials.

At the top of the page they point newcomers to the workshop titled “LearnYouNode”. This workshop has the subtitle “Learn You The Node.js For Much Win!” This raised my eyebrows. It wasn’t immediately obvious that the broken English was a running gag of some sort. I don’t know what it is… maybe LOLcat?

Not knowing it was a gag, I thought maybe the tutorial were written by people for whom English was not their primary language. I was worried I would get stuck trying to figure out if I’m misunderstanding broken English or misunderstanding Node.js.

Fortunately, it only took a paragraph of two of tutorial instructions to make it clear the lessons are not, in fact, broken English. Which was very good news because there was very little hand-holding. The audience is presumed to be competent developers off the bat. It actually assumed JavaScript skill level a bit higher than what I have! Fortunately close enough I could get through with some educational web searches.

The overview workshop sped me through some Node.js basics. Even better: After I successfully completed each challenge, it will show me the official answer which inevitably differed from my solution. I learned a lot from the answer key source code which I hope will help my JavaScript skills going forward.

One of the things LearnYouNode introduced me to is NPM. The Node.js Package Manager came up repeatedly in many of my previous explorations, and I knew I had to get a handle on it soon. I’ve only got a taste so far, and there’s a whole other workshop dedicated to the topic. I think that’s a good place to go next.

jQuery Learning Center

After Codecademy got me off the ground with jQuery, I moved on to the jQuery Learning Center put together by the people behind the jQuery project. The learning center assumes some level of existing knowledge, so I was glad I got the Codecademy primer first.

As expected, the jQuery Learning Center went into more depth on topics that were outside of a quick primer such as Codecademy.

Implementation: The learning center gave some details on how jQuery works behind the scenes. This helps programmers understand and debug when things go wrong, and sometimes leads to information on code performance.

Performance: Hand in hand with implementation details, the learning center teaches some basics on writing efficient jQuery code. This is different from writing terse jQuery code. What looks like small amounts of jQuery code might end up triggering a lot of work for the computer behind the scenes. A programmer unaware of the implementation and performance consequences can get tripped up.

History: The learning center occasionally switches into history lesson mode. It is moderately enlightening to understand the evolution to the current implementation. More importantly, it helps people recognize and understand old legacy jQuery code they might end up having to maintain.

Code organization: This section was not jQuery specific. It covered a few ways to use JavaScript to implement classic object-oriented programming concepts. I was intrigued by this section, because it didn’t match what I saw in the Codecademy JavaScript class. It is useful to get a different perspective on how to solve the same types of problems.

It was good timing. My own JavaScript practice program had not been written under any semblance of code organization, just building as I go, and it was growing out of control. Seeing how messy things were turned out to be great motivation to put organization concepts into practice and tame my hairy beast.

JavaScript closures make my head spin

Coming from a world of strongly typed programming languages, JavaScript is weird. And the deeper I get, the weirder it got.

I’ve had brushes with JavaScript closures in my learning to date, and the fragments I saw looked like evil black magic. Today I dove in headfirst to learn more about it.  With my new found knowledge, it no longer feels like black magic.

It still feels evil, though.

Closures have all the appearance of something that “fell out” of the flexibility of the JavaScript type system. It felt like somebody, in an effort to solve some unrelated problems A, B, and C, accidentally opened a Pandora’s Box and closures emerged. With some bizarre behavior and huge potential for difficult-to-diagnose bugs. I’d hate to think it was designed to be that way. I prefer to believe it was an accident.

Accident or not, it is a very powerful mechanism and people are using it in the world. Which means I will need to be able to read and understand code that uses closures. It is irrelevant whether I personally believe closures are evil.

It’ll take a few more rounds of practice before I’m comfortable with the nuances. In the meantime, I’ll be reviewing this page frequently as I found it to be the most helpful. The author emphasized repeatedly that hands-on experience with real closure code is more illuminating than reading a lot of rigorous academic style description of closures. So that’s exactly what I intend to do.


The best I can hope for is to start feeling comfortable with the power and pitfall of closures. Maybe I’ll even come to appreciate it as a necessary evil.

But I doubt I’ll ever come to think of it as A Good Thing.

Compilation of JavaScript resources

The benefit of JavaScript is that there are a ton of resources. The downside of JavaScript is that there is so much, it’s hard to figure out where to start and who to believe.

After the expected period of beginner fumbling, I now know a few things to be incorrect. But more importantly, I now know many things to have no single Right Answer(™). JavaScript is so flexible that there are many ways to do many things and not much to differentiate one from another except personal preference.

This makes me wary of advice compiled on somebody’s blog, because that’s really their personal opinion and I don’t know if I necessarily agree with that person’s priorities.

But if the collection of resources was assembled by a group of people, that makes me a little more comfortable. So I was happy to stumble across

The name seemed pompous and arrogant, but the introduction made me feel like I’ve found a good thing:

This is a guide intended to introduce new developers to JavaScript and help experienced developers learn more about its best practices.

Despite the name, this guide doesn’t necessarily mean “the only way” to do JavaScript.

We just gather all the articles, tips, and tricks from top developers and put it here. Since it comes from exceptional folks, we could say that it is “the right way”, or the best way to do so.

I’ll be coming back to this page quite frequently. May it live up to my hopes!