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.

rauschma

Strings

String.prototype.*

None of the string methods modify this – they always return fresh strings.

• charAt(pos: number): string ^ES1

  Returns the character at index pos, as a string (JavaScript does not have a datatype for characters). str[i] is equivalent to str.charAt(i) and more concise (caveat: may not work on old engines).

mtpereira

apiVersion: v1
kind: ReplicationController
metadata:
  name: kube-registry-v0
  namespace: kube-system
  labels:
    k8s-app: kube-registry
    version: v0
spec:
  replicas: 1

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

beaugunderson

from streams session

• end-of-stream - specify a callback to be called when a stream ends (which is surpsingly hard to get right)
• duplexify - compose a Duplex stream from a Readable and a Writable stream
• pump - pipe streams together and close all of them if one of them closes
• pumpify - combine an array of streams into a single duplex stream using pump and duplexify
• through2 - tools for making Transform streams
• from2 - tools for making Readable streams

from "participatory modules" session

nkbt

{
  "env": {
    "browser": true,
    "node": true,
    "es6": true
  },

  "plugins": ["react"],

  "ecmaFeatures": {

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---

branneman

Better local require() paths for Node.js

Problem

When the directory structure of your Node.js application (not library!) has some depth, you end up with a lot of annoying relative paths in your require calls like:

const Article = require('../../../../app/models/article');

Those suck for maintenance and they're ugly.

Possible solutions

creationix

Generators vs Fibers

Both ES6 generators and node-fibers can be used to block a coroutine while waiting on some I/O without blocking the entire process. Both can do this for arbitrarily deep call stacks. The main difference between the capabilities of the two is how explicit the syntax is.

Generators - Safe, but Explicit

In code that uses ES6 generators:

var run = require('gen-run'); // https://github.com/creationix/gen-run

jakimowicz

#!/usr/bin/env ruby

require 'faraday'
require 'json'
require 'gitlab'

module Redmine
  Host = nil
  APIKey = nil