jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

iwek

//return an array of objects according to key, value, or key and value matching
function getObjects(obj, key, val) {
    var objects = [];
    for (var i in obj) {
        if (!obj.hasOwnProperty(i)) continue;
        if (typeof obj[i] == 'object') {
            objects = objects.concat(getObjects(obj[i], key, val));    
        } else 
        //if key matches and value matches or if key matches and value is not passed (eliminating the case where key matches but passed value does not)
        if (i == key && obj[i] == val || i == key && val == '') { //

addyosmani

CSS Layout Debugger

A tweet-sized debugger for visualizing your CSS layouts. Outlines every DOM element on your page a random (valid) CSS hex color.

One-line version to paste in your DevTools

Use $$ if your browser aliases it:

~ 108 byte version

ejoubaud

// Based on http://stackoverflow.com/a/10520017/1307721 and http://stackoverflow.com/a/16022728/1307721

Podium = {};

Podium.keydown = function(k) {
    var oEvent = document.createEvent('KeyboardEvent');

    // Chromium Hack
    Object.defineProperty(oEvent, 'keyCode', {
                get : function() {

nkbt

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

  "plugins": ["react"],

  "ecmaFeatures": {

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

fdecampredon

import React from 'react';
import { container } from 'redux-relay';



@container({
  variablesFromState: (state) => ({myVariable: state.myState})
  fragments: {
    Relay.QL`
      viewer {

ryanflorence

Turning Off Github Issues

My friend Michael Jackson turned off github issues on one of his smaller projects. It got me thinking...

Maintainers getting burned out is a problem. Not just for the users of a project but the mental health of the maintainer. It's a big deal for both parties. Consumers want great tools, maintainers want to create them, but maintainers don't want to be L1 tech support, that's why they

marcysutton

import {expect} from 'chai';
import App from '../app/components/App';

import a11yHelper from "./a11yHelper";

describe('Accessibility', function () {
  this.timeout(10000);

  it('Has no errors', function () {
    let config = {};

gcanti

/* @flow */

import React from 'react'
import ReactDOM from 'react-dom'

type FunctionComponent<A> = (props: A) => ?React$Element<any>;

type ClassComponent<D, A, S> = Class<React$Component<D, A, S>>;

type Component<A> = FunctionComponent<A> | ClassComponent<any, A, any>;