Javascript 检查对象是否具有使用字符串变量定义的函数

给定以下代码，我想使用变量

fn

检查

someObject

是否具有

bar

函数

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();

---

this[fn]（）+
fn在这种类型的[fn]
@Subash-怎么会这样？我刚试过。很好用。与其说它错了，不如解释它的错在哪里。我满足了你提出的要求。如果这是不正确的，你应该解决这个问题。
if (typeof this[fn] === 'function') {
    this[fn]();
}