Attach Event Listener to Array for Push() Event

You could use an ‘eventify’ function that overrides push in the passed array.

var eventify = function(arr, callback) {
    arr.push = function(e) {
        Array.prototype.push.call(arr, e);
        callback(arr);
    };
};

In the following example, 3 alerts should be raised as that is what the event handler (callback) does after eventify has been called.

var testArr = [1, 2];

testArr.push(3);

eventify(testArr, function(updatedArr) {
  alert(updatedArr.length);
});

testArr.push(4);
testArr.push(5);
testArr.push(6);