Update June, 2017: Subject to support (e.g. if you’re not running JavaScript in Internet Explorer 10 or below), you should look into using let instead of var. For example: for(let i=0; …; i++) There’s no way I’m going to put var i; from a for(var i=0; …; i++) at the top of my functions. Especially … Read more
JSLint suggests you use other loops such as forEach. http://www.jslint.com/help.html#for You can just select the tolerate “for statement” option at the bottom if this bothers you but the code looks fine.
Partially it depends on whether you’re using a function expression or a function declaration. They’re different things, they happen at different times, and they have a different effect on the surrounding scope. So let’s start with the distinction. A function expression is a function production where you’re using the result as a right-hand value — e.g., … Read more
In addition to breaking === and typeof returning “object”, using the Number constructor also changes the way the value is used in boolean contexts. Since “new Number(0)” is an object, not a literal value, it evaluates as “true” because it is not null. So for example: var n1 = 0; var n2 = new Number(0); … Read more
TL;DR Use JSLint if you’re looking for a very high standard for yourself or your team, but bear in mind that it’s not necessarily the standard, only a standard, some of which comes to us dogmatically from Doug Crockford. If you want to be a bit more flexible or have some old pros on your … Read more
Include ‘use strict’; as the first statement in a wrapping function, so it only affects that function. This prevents problems when concatenating scripts that aren’t strict. See Douglas Crockford’s latest blog post Strict Mode Is Coming To Town. Example from that post: (function () { ‘use strict’; // this function is strict… }()); (function () … Read more
array literal notation is where you define a new array using just empty brackets. In your example: var myArray = []; It is the “new” way of defining arrays, and I suppose it is shorter/cleaner. The examples below explain the difference between them: var a = [], // these are the same b = new … Read more
It’s safer to use [] than it is to use new Array(), because you can actually override the value of Array in JavaScript: Array = function() { }; var x = new Array(); // x is now an Object instead of an Array. In other words, [] is unambiguous.
Extending @KooiInc answer, you can avoid manually escaping every special character by using the source property of the RegExp object. Example: var urlRegex= new RegExp(” + /(?:(?:(https?|ftp):)?\/\/)/.source // protocol + /(?:([^:\n\r]+):([^@\n\r]+)@)?/.source // user:pass + /(?:(?:www\.)?([^\/\n\r]+))/.source // domain + /(\/[^?\n\r]+)?/.source // request + /(\?[^#\n\r]*)?/.source // query + /(#?[^\n\r]*)?/.source // anchor ); or if you want to … Read more
tl;dr If you’re not calling anything until everything loads, you should be fine. Edit: For an overview which also covers some ES6 declarations (let, const): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Scope_Cheatsheet This weird behavior depends on How you define the functions and When you call them. Here’s some examples. bar(); //This won’t throw an error function bar() {} foo(); //This … Read more