Accessing an object's property from an event listener call in Javascript

Question

Below I am creating an object in Javascript. Within the constructor I am setting up an event listener. The problem is that when the event gets fired, this.prop cannot be fou

Answer 1

The javascript built-in Function.prototype.bind() is intended for this purpose.
For example:

var someObj = function someObj(){
       this.prop = 33;
        this.mouseMoving = function() { console.log(this.prop);}

        document.getElementById("someDiv").addEventListener('mousemove', this.mouseMoving.bind(this),true);

 }

More on the bind method here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

Other wise you have to pass a reference of the object someObj to the element and use that reference in the line:

console.log(this.referenceToObject.prop); //this references the DOM element in an event.