Fintan Fintan

What's wrong with Netmag's "Optimize your JavaScript" post

Update: The original post on Netmag has been updated since this was written.

I tweeted earlier that this should be retracted. Generally, these performance-related articles are essentially little more than linkbait -- there are perhaps an infinite number of things you should do to improve a page's performance before worrying about the purported perf hit of multiplication vs. division -- but this post went further than most in this genre: it offered patently inaccurate and misleading advice.

Here are a few examples, assembled by some people who actually know what they're talking about (largely Rick Waldron and Ben Alman, with some help from myself and several others from the place that shall be unnamed).

	Navigation:

	cmd-p Goto Anything ('@' for functions, ':' for line number)
	cmd-r Function finder
	ctl-g Goto line number
	cmd-sft-p Command palette
	cmd-sft-f Find in Files
	cmd-opt-r Toggle regex when finding
	cmd-opt-# Columns
	ctr-# Switch columns

	var application_root = __dirname,
	express = require("express"),
	path = require("path"),
	mongoose = require('mongoose');

	var app = express.createServer();

	// database

	mongoose.connect('mongodb://localhost/ecomm_database');


	/**
	* @constructor
	*/
	function Injector() {

	/**
	* @type {!Object.<string, function(Injector=): !Object>}
	*/
	this.factories = {};

	/**
	* Assign a value to the delimited key in the given object. The inverse of `_.lookup`
	*
	* @example
	*
	* var myObj = {};
	*
	* _.assign(myObj, 'foo.bar', 'baz'); // myObj = { foo: { bar: 'baz' }}
	*
	* @param {Object} obj the object to assign to

	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
	<html>
	<head>
	<link rel="stylesheet" href="http://code.jquery.com/qunit/git/qunit.css" type="text/css" media="screen" />

	<!-- when.js Promises implementation -->
	<script src="https://raw.github.com/cujojs/when/master/when.js"></script>

	<!-- Unit testing and mocking framework -->
	<script type="text/javascript" src="http://code.jquery.com/qunit/git/qunit.js"></script>

	class JQ
	{
	static public inline function select(j:js.Dom.HtmlDom):js.JQuery
	{
	return new js.JQuery(j);
	}

	static public inline function query(j:String):js.JQuery
	{
	return new js.JQuery(j);

	_.mixin({

	// Get/set the value of a nested property
	deep: function (obj, key, value) {

	var keys = key.replace(/\[(["']?)([^\1]+?)\1?\]/g, '.$2').replace(/^\./, '').split('.'),
	root,
	i = 0,
	n = keys.length;

	import haxe.macro.Expr;

	class Main {
	static function main() {
	var a = generateCharCodeArray("foobar");
	trace(a); // [102,111,111,98,97,114]
	}

	#if haxe_211
	@:macro static public function generateCharCodeArray(source:String) {

	.PHONY: compile

	time=/usr/bin/time

	compile: dart typescript coffeescript haxe jsx

	dart:
	$(time) dart2js -ooutput/dart.js source/simple.dart

	typescript:

Fintan Fintan

What's wrong with Netmag's "Optimize your JavaScript" post

Things that are just plain wrong