Javascript accessing functions of same class

Question

In the following code:

function xyz(x) {
          //something
          this.x = x;
        }
        xyz.prototype = {
            a: function () {
                //do something
            },
            b: function () {
                //pre
                this.a();
                //post
            }
        }

the call of this.a() gives the warning of method not supported. So I tried using xyz.prototype.a.call(this) instead. But it does not maintain the value of x. What do I do to call one method of a class from other?

You did not show how function "b()" is called when you run into that error. — Pointy
– Pointy, Commented Oct 1, 2011 at 13:02
This obviously instead the actual code, right? Method not supported is return from the web server if it only has GET and you try to POST or anyother non-support/implemented verb — Joe
– Joe, Commented Oct 1, 2011 at 13:03

Pointy · Accepted Answer · 2011-10-01 13:01:58Z

Given your code, if you write:

var myXyz = new xyz("hello");

then calling

myXyz.b();

should correctly get to the "a()" function on the prototype. However, if you do something like this:

var otherB = myXyz.b;

otherB();

then it will not work, because there's no context object (that is, the this value inside "b()" won't be set correctly to an instance of "xyz"). That often happens when a function is being used as an event handler:

 something.onclick = myXyz.b;

The event handler, when called, won't have an "xyz" instance to work with. Instead of that, therefore, you could write:

 something.onclick = function() { myXyz.b(); };

which clearly ensures that there's an "xyz" object.

Collectives™ on Stack Overflow

Javascript accessing functions of same class

1 Answer 1

Comments

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Related