Check if object has function defined using a string variable

Question

Given following code, I want to check if someObject has bar function using the variable fn.

var SomeObject = function() {};
SomeObject.prototype.foo = function() {
 var fn = 'bar';
 // todo: I want to check if this object has 'bar' function.
 // if yes call it
 // Note: you can't do if(typeof this.bar === 'function')
 // got to use the variable fn
};
var OtherObject = function() {
 SomeObject.call(this);
};
OtherObject.prototype = Object.create(SomeObject.prototype);
OtherObject.prototype.bar = function() {
 console.log('great. I was just called.');
};
var obj = new OtherObject();
obj.foo();

• zerkms: this[fn](); + fn in this + typeof this[fn]

Answer 1

if (typeof this[fn] === 'function') {
 this[fn]();
}

• Antiokus: @Subash - how so? I just tried it. works just fine. instead of saying it's wrong, explain what is wrong about it. I satisfied the requirements you gave. If that is incorrect, you should address that.