A blog about design, code and some other stuff

On high-level languages like JavaScript we usually don’t care about how the objects are stored in the memory, we let the VM handle it for us, and since the language contains Arrays most users never find a need for Linked Lists even tho it’s a very powerful and useful data structure.

Like most front-end developers I don’t have a Computer Science degree and started to program using high level languages, it took me a while to stumble into Linked Lists, that’s why I’m going to explain the basic use cases, pros/cons of this simple data-structure and why it’s widely used. - You probably used it before without knowing.

This post was motived by this tweet:

Can anyone explain what a Linked List is and why I’d use one (if I even could in Ruby, PHP, JS). I’m not quite grokking their purpose?— integralist (@integralist) May 12, 2013

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This weekend I spent some time improving the structure of some of my open source projects repositories and also finally decided to add a Travis-ci hook to the most active/newest ones.

Travis is a free continuous integration server for open source projects that can be used to automate tests and help you deal with projects that have multiple contributors. If you are familiar with GitHub you probably seen their build status icons on a few projects before (on the image above). It can be used to test multiple languages like JavaScript, PHP, Python, Ruby, Java and many others. It also have options to notify the project maintainers every time the build status changes or on each commit. (email, IRC, campfire, etc)

It is really easy to setup it if your tests are already executed on the command line. If the tests needs a browser to work you can hook a headless browser like PhantomJS. - For my projects I’m just executing the tests on node.js for now since that should be enough to catch most errors. - Having a headless browser can help to double check if the code works on multiple environments.

Travis documentation is very clear and the amount of boilerplate is minimal, for a regular node.js project you just need a file named .travis.yml on the root folder containing:

 language: node_js
 node_js: 0.8

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Some of the most popular Node.js test frameworks advertise that they should be installed globally: Jasmine, Mocha, Buster.js, etc… I consider this an anti-pattern.

am I the only one who find it “weird” that all (popular) node.js test frameworks uses a global install?

— Miller Medeiros (@millermedeiros) October 25, 2012

On this post I will try to explain why it’s an anti-pattern and show how to avoid global installs by using npm test instead.

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The RequireJS behavior changed from version 1.0 to 2.0. Now module dependencies are only loaded after a explicit require() call or if it is on the dependency tree of some of the require‘d modules. That means that the module factory (define callback) won’t execute unless it is needed. That is a huge win for many reasons, less work for the JS engine and code has the same behavior before and after build. It also makes it possible to create alias to complex modules without triggering a download.

On my current project I have ~15 JS widgets that can be placed on any page and the amount of JS required by each widget is small so it makes sense to bundle all the JS into a single file for production (<30KB minified + gzipped excluding jQuery) instead of loading things on demand (a single request have better perf results than multiple requests in many cases).

I will show a very simple technique I used on the project to create an alias to the Google Maps API since I think it can be useful to other people as well in different contexts.

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There are a lot of build tools that covers specific use cases and/or try to cover as many scenarios as possible, amongst the most famous ones are make, rake, Ant and maven. I’m going to talk about why I’ve been favoring plain Node.js scripts as my “build tool” and how to do some simple things. This work flow may not be the best one for you and your team, understand the reasoning behind it and pick the tools based on your needs and preferences.

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