ParsleyJS - declarative form validation JavaScript library.
Note
slavcodev made autoloader extension to use Upper Case namespaces in Yii2. And now if you really mind it - you can use Yii\Web\Controller instead of use yii\web\Controller.
в MobiDev (Харьков, Украина)
Code in Ruby and Elixir, but still love PHP. Explore ES6 and Vue.js. Explore databases, use Ubuntu and MacOS, think about IT people and management
Заметки
Promise nuggets a github-book by @spion with good explanation and examples for Promises usage. Mostly on Promises alternative to async callbacks approach.
Bluebird - javascript promises library aimed to be almost "as fast as regular callback code" (and 100/10 times faster then Q and when). Worth to try out.
I was waiting for it so long :) Videoconverter.js - FFmpeg converted in JavaScript via Emscripten. It works in client browser, really works. It does not support x264 codec yet, but could be useful to create a video preview on client side etc.
How to install and copy CSS/JS resources via Composer using Composer plugin.