JavaScript recommendations

Question

This is somewhat related to this question , but I am not asking for resources on best practices in JavaScript, but your actual advice.

I will start with my own list. You can either post the answer or directly edit the question if you are sure that the advice is not inconsistent.

Here we go:

• always use var
• uppercase constructor function names - and nothing more
• use ===for comparison
• use explicit casts for primitives, for example. Number(), String(),Boolean()
• check primitive types with typeof
• check object types with instanceof

• check the built-in types of objects with Object.prototype.toString()to avoid problems with multiple frames, for example

  Object.prototype.toString.call(obj) === '[object Array]'
  

• this ,

  function MyObject() {
      if(!(this instanceof arguments.callee))
          throw new Error('constructor called with invalid `this`');
      // [...]
  }
  

• , ,

  (function() {
      var noGlobalVar = 'foo';
      // [...]
  })();
  

• hasOwnProperty() for..in - ,

• for..in , .

Answer 1

. - Array.prototype - , , .

, . - .

, . , jQuery, , , :

(function($) {
    /* Lots of code */
})(jQuery);

Answer 2

, . Number(), String(), Boolean()

? , . ?

Answer 3

:

, . , , break continue , if.

Answer 4

jslint.

, .

Jslint will tell you if you break one or more "best practices."

Also consider using an IDE that supports jslint. I can recommend WebStorm or Sublime Text 2 (I tested these 2 myself, and they support jslint very well).