(by @andrestaltz)
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.
(by @andrestaltz)
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.
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.
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.
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
let cache = new Map(); | |
let pending = new Map(); | |
function fetchTextSync(url) { | |
if (cache.has(url)) { | |
return cache.get(url); | |
} | |
if (pending.has(url)) { | |
throw pending.get(url); | |
} |
body { | |
background-image: | |
linear-gradient(45deg, #ccc 25%, transparent 25%), | |
linear-gradient(135deg, #ccc 25%, transparent 25%), | |
linear-gradient(45deg, transparent 75%, #ccc 75%), | |
linear-gradient(135deg, transparent 75%, #ccc 75%); | |
background-size:25px 25px; /* Must be a square */ | |
background-position:0 0, 12.5px 0, 12.5px -12.5px, 0px 12.5px; /* Must be half of one side of the square */ | |
} |
This article has been given a more permanent home on my blog. Also, since it was first written, the development of the Promises/A+ specification has made the original emphasis on Promises/A seem somewhat outdated.
Promises are a software abstraction that makes working with asynchronous operations much more pleasant. In the most basic definition, your code will move from continuation-passing style:
getTweetsFor("domenic", function (err, results) {
// the rest of your code goes here.
// http://paulirish.com/2011/requestanimationframe-for-smart-animating/ | |
// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating | |
// requestAnimationFrame polyfill by Erik Möller. fixes from Paul Irish and Tino Zijdel | |
// MIT license | |
(function() { | |
var lastTime = 0; | |
var vendors = ['ms', 'moz', 'webkit', 'o']; |
This is a collection of the things I believe about software development. I have worked for years building backend and data processing systems, so read the below within that context.
Agree? Disagree? Feel free to let me know at @JanStette. See also my blog at www.janvsmachine.net.
Keep it simple, stupid. You ain't gonna need it.
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* Licensed under the Apache License, Version 2.0 (the "License"); | |
* you may not use this file except in compliance with the License. | |
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