Question

29

Array change listener

rated 0 times [ 36] [ 7] / answers: 1 / hits: 17158 / 12 Years ago, tue, december 11, 2012, 12:00:00

Possible Duplicate:

Javascript - How to extend Array.prototype.push()?

How can I be notified (run a pre-defined function) of any change to a registered array (or at least any addition or removal of elements)?
I tried using prototype. I don't want to be scolded for not providing SOME code examples of my own. So here's how I would like to use it.

var myArray = [];

myArray.bind(function() {

    console.log('wtf'); // Wed Thu Fri and what were you thinking?

});

I don't need overkill. I basically know the Array function scope that I will be using (push, pop, splice and maybe a couple others). It's a way to use backbone's MVC. I want to run logic on an array and THEN have the views highlighted accordingly. But the view is already attached to a collection. Any change to that collection re-renders the actual DOM's in the view. I don't want that. I simple want to add, or remove, a class to the corresponding DOM's in the view for CSS purposes.

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breonnamayah

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1 Year ago

answered 12 Years ago leslijessalyng · Accepted Answer

What I did is I made my own array type that just extended the prototype array, which then I added my own handlers to.

For example:

var MyArray = function() {

    var arr = [];

    arr.push = function() {

        console.log(PUSHING, arguments);

        return Array.prototype.push.apply(this, arguments);

    }



    return arr;

};

Usage:

var arr = new MyArray;

arr.push(12, 3, 45);

...

Fiddle: http://jsfiddle.net/maniator/vF659/