Question

Now I have a prototype like:

function A() {}

A.prototype.run =  function () {
    console.log('run 1');
};

Given that I cannot change anything where A is at (no control over the source). I would like to extend the method run. Not only log run 1, also log run 2. I tried several different approaches, it does not work.

A.prototype.run = function () {
    this.run.call(this);
    console.log('run 2');
}

Or

A.prototype.run = function () {
    arguments.callee.call(this);
    console.log('run 2');
}

Anyone having a solution for this? I would rather not to copy what’s inside the method run. Thanks!

Answer 1

A.prototype._run = A.prototype.run;
A.prototype.run = function () {
    this._run.call(this);
    console.log('run 2');
}