| // v1 attempt | |
| // This version passes all tests. However, it's missing a couple of key features: | |
| // (1) it only takes one 'level' of dependencies (no nested dependencies), and | |
| // (2) dependencies must have already been loaded in order for a library to be loaded. | |
| (function() { | |
| var libraryStorage = {}; | |
| function librarySystem(libraryName, dependencyArray, callback) { | |
| if (arguments.length > 1) { |
#Understanding closures, callbacks and promises
For a code newbie like myself, callbacks, closures and promises are scary JavaScript concepts.
10 months into my full-time dev career, and I would struggle to explain these words to a peer.
So I decided it was time to face my fears, and try to get my head around each concept.
Here are the notes from my initial reading. I'll continue to refine them as my understanding improves.
| function mapValues(obj, fn) { | |
| return Object.keys(obj).reduce((result, key) => { | |
| result[key] = fn(obj[key], key); | |
| return result; | |
| }, {}); | |
| } | |
| function pick(obj, fn) { | |
| return Object.keys(obj).reduce((result, key) => { | |
| if (fn(obj[key])) { |
All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.
Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.
elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent
I heard from GitHub Two-Factor Authentication](https://github.com/blog/1614-two-factor-authentication) nearly a couple of days ago when I was reading my RSS feed. I enabled it and couldn' push to any of my repositories anymore. Learn in this blog post how to fix it.
"Is a process involving two stages to verify the identity of an entity trying to access services in a computer or in a network". Github solves this authentication with sending an SMS to a device which wants to push to their platform.
| echo 'export PATH=$HOME/local/bin:$PATH' >> ~/.bashrc | |
| . ~/.bashrc | |
| mkdir ~/local | |
| mkdir ~/node-latest-install | |
| cd ~/node-latest-install | |
| curl http://nodejs.org/dist/node-latest.tar.gz | tar xz --strip-components=1 | |
| ./configure --prefix=~/local | |
| make install # ok, fine, this step probably takes more than 30 seconds... | |
| curl https://www.npmjs.org/install.sh | sh |