CODEWITHSUNDEEP
javascriptobjectmootools
Chris Baker
Chris Baker

Reputation: 50602

Memory efficiency in objects

Is either of these patterns more or less efficient than the other?

Pattern 1:

var jso = new Class({
   initialize: function () {
     // code
   },
   hiliteField: function () {
     // code
   }
});

Pattern 2:

var jso = new Class({
   initialize: function () {
     this.hiliteField = hiliteField.bind(this);
     // code  
   }
});
var hiliteField = function () {
  // code
}

Upvotes: 0

Views: 200

Answers (2)

digitarald
digitarald

Reputation: 1862

Pattern 2 will use more memory! It's the basics of prototypal inheritance

Why? In Pattern 1 every instance of jso will reference jsoInstanceX.hiliteField to jso.prototype.hiliteField. Read: hiliteField will not be a copy, it will only exist in jso.prototype.

In Pattern 2 you create a function wrapper each time you assign hiliteField.bind(this);. The additional memory is not much, but it's also slower, especially with impact on Class initialization.

Upvotes: 1

Dimitar Christoff
Dimitar Christoff

Reputation: 26165

Having multiple methods that are external to the class and up the scope chain, as opposed to behind the class as 'namespaced' methods can't be better, imo.

Don't like pattern #2 for several reasons:

  • manageability - having to bind a reference to each external function into the class is going to be hard to do.
  • readability - having to indicate which function is being used by what class is going to be a task
  • extendibility - because the functions are outside of the jso class prototype, classes that extend jso or use it as a mixin won't be able to access the external methods.

That being said, from a memory standpoint - just do a test but I would say, pattern 1 is likely to have a smaller overhead because it's defined once on the prototype and not in every instance individually.

Upvotes: 1

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