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
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
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
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
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
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.
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
There’s no difference. Both are valid ways to get the JavaScript parser to treat your function as an expression instead of a declaration. Note that + and ! will also work, and are sometimes used by minifiers to save a character of size: +function() { var foo = ‘bar’; }(); !function() { var foo = … Read more
From Douglass Crockford’s style convention guide: (search for “invoked immediately”) When a function is to be invoked immediately, the entire invocation expression should be wrapped in parens so that it is clear that the value being produced is the result of the function and not the function itself. So, basically, he feels it makes more … Read more
Douglas Crockford has a new idiomatic way of achieving the above – his old technique was to use an inner function to bind the variables, but the new technique uses a function maker. See slide 74 in the slides to his “Function the Ultimate” talk. [This slideshare no longer exists] For the lazy, here is … Read more