Comments on: Checking types in JavaScript

By: GeekFG

GeekFG — Wed, 14 Jan 2009 10:38:13 +0000

That’s why a added this link “http://docs.jquery.com/JQuery_Core_Style_Guidelines”.
When I want to check for an array I use jQuery.isArray(object).

Moreover Object.prototype is a better way for browsers compatibility than window[key] = function(){}

By: James

James — Wed, 14 Jan 2009 09:17:48 +0000

@GeekFG, did you read my post (or any of the other comments)? Typeof is okay for most cases but it reports certain types incorrectly. For example, this won’t work:

alert( typeof [1,2,3,4,5] ); // This should alert 'Array', not 'Object'

By: GeekFG

GeekFG — Wed, 14 Jan 2009 09:11:09 +0000

Why did you not simply use typeOf (http://docs.jquery.com/JQuery_Core_Style_Guidelines) ?

By: Gman

Gman — Wed, 14 Jan 2009 02:58:48 +0000

@James
ya, now I got it. Thank you

By: Ryan Townsend

Ryan Townsend — Mon, 12 Jan 2009 19:37:43 +0000

Paul, those guidelines do prevent use of a switch() condition though, for better code-readability James’ method works nicely.

By: Pete

Pete — Mon, 12 Jan 2009 19:35:39 +0000

nice idea

By: Paul Irish

Paul Irish — Mon, 12 Jan 2009 18:48:04 +0000

just for reference, here are the official recommendations for doing these in jQuery: http://docs.jquery.com/JQuery_Core_Style_Guidelines

By: James

James — Mon, 12 Jan 2009 17:36:54 +0000

Hi Gman!

‘===’ is known as the strict equality operator. It is normally used instead of the well known general equality operator (‘==’). The only difference is that the former checks for type and the latter doesn’t. It’s best practice to use the strict version for that very reason.

An example:

var realNumber = 999;
var numberInString = '999';
 
realNumber == numberInString; // TRUE
realNumber === numberInString; // FALSE

By: Gman

Gman — Mon, 12 Jan 2009 17:27:52 +0000

what does “===” mean?