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

From Section 4.3 of JavaScript: The Good Parts by Douglas Crockford:

Invoking a function suspends the execution of the current function, passing control and parameters to the new function. In addition to the declared parameters, every function receives two additional parameters: this and arguments. The this parameter is very important in object oriented programming, and its value is determined by the invocation pattern. There are four patterns of invocation in JavaScript: the method invocation pattern, the function invocation pattern, the constructor invocation pattern, and the apply invocation pattern. The patterns differ in how the bonus parameter this is initialized.

Crockford continues to explains the binding of 'this' in each of these patterns, as follows:

The Method Invocation Pattern: When a function is stored as a property of an object, we call it a method. When a method is invoked, this is bound to that object.

The Function Invocation Pattern: When a function is invoked with this pattern, this is bound to the global object. This was a mistake in the design of the language.

The Constructor Invocation Pattern: If a function is invoked with the new prefix, then a new object will be created with a hidden link to the value of the function's prototype member, and this will be bound to that new object.

The Apply Invocation Pattern: The apply method lets us construct an array of arguments to use to invoke a function. It also lets us choose the value of this. The apply method takes two parameters. The first is the value that should be bound to this. The second is an array of parameters.