gaearon

Note:

When this guide is more complete, the plan is to move it into Prepack documentation.
For now I put it out as a gist to gather initial feedback.

A Gentle Introduction to Prepack (Part 1)

If you're building JavaScript apps, you might already be familiar with some tools that compile JavaScript code to equivalent JavaScript code:

• Babel lets you use newer JavaScript language features, and outputs equivalent code that targets older JavaScript engines.

sebmarkbage

The Rules of React

All libraries have subtle rules that you have to follow for them to work well. Often these are implied and undocumented rules that you have to learn as you go. This is an attempt to document the rules of React renders. Ideally a type system could enforce it.

What Functions Are "Pure"?

A number of methods in React are assumed to be "pure".

On classes that's the constructor, getDerivedStateFromProps, shouldComponentUpdate and render.

Danilo-Araujo-Silva

For example, to override the AppBar (https://material-ui-next.com/api/app-bar/) root class we can do the following:

First method (override Material UI classnames):

1 - Add the property classes in the AppBar component:

    <AppBar classes={{root: 'my-root-class'}}

SheldonWangRJT

This notes is written by Sheldon. You can find me with #iOSBySheldon in Github, Youtube, Facebook, etc.

Need

Convert .mov/.MP4 to .gif

Reason

As a developer, I feel better to upload a short video when I create the pull request to show other viewers what I did in this PR. I tried .mov format directly got after finishing recording screen using Quicktime, however, gif offers preview in most web pages, and has smaller file size.

This is not limited to developer, anyone has this need can use this method to convert the files.

ggregoire

TL;DR

If you mix JS event listeners and React event listeners, you need

event.nativeEvent.stopImmediatePropagation()

Scenario

Rich-Harris

Stuff I wish I'd known sooner about service workers

I recently had several days of extremely frustrating experiences with service workers. Here are a few things I've since learned which would have made my life much easier but which isn't particularly obvious from most of the blog posts and videos I've seen.

I'll add to this list over time – suggested additions welcome in the comments or via twitter.com/rich_harris.

Use Canary for development instead of Chrome stable

Chrome 51 has some pretty wild behaviour related to console.log in service workers. Canary doesn't, and it has a load of really good service worker related stuff in devtools.

paulirish

What forces layout / reflow

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.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

mridgway

/**
 * On server, just register all of the resources directly to the plugin. On the client, pass in a loader file that maps bundle
 * name to webpack bundle require (a separate entry point). Then from your action, you can call `context.loadBundle` to load
 * the bundle resources. On the server, the resources are already available but on the client they will be lazy loaded by
 * webpack.
 */
'use strict';
var debug = require('debug')('BundlePlugin');
var PromiseLib = global.Promise || require('es6-promise').Promise;

brianclements

Commit Message Format

This specification is inspired by and supersedes the [AngularJS commit message format][commit-message-format].

We have very precise rules over how our Git commit messages must be formatted. This format leads to easier to read commit history.

Each commit message consists of a header, a body, and a footer.

z5h

/** @jsx React.DOM */
"use strict";

var util = {

  // findPos() by quirksmode.org
  // Finds the absolute position of an element on a page
  findPos: function (obj) {
    var curleft = 0,
        curtop = 0;