Extending Math object through prototype doesn't work

Question

I try to extend JavaScript Math. But one thing surprised me.

When I tried to extend it by prototype

Math.prototype.randomBetwee         


        

Answer 1

var MyMath = Object.create(Math); // empty object with prototype Math

MyMath.randomBetween = function (a, b) {
    return this.floor(this.random() * (b - a + 1) + a);
};

typeof(MyMath);                 // object
Object.getPrototypeOf(MyMath);  // Math
MyMath.PI;                      // 3.14...
MyMath.randomBetween(0, 10);    // exactly that

• the Math object is the prototype of the new MyMath object
• MyMath has access to all functionality of Math
• you can add your custom functionality to MyMath without manipulating Math
• within your custom methods, use keyword this to refer to the Math functionality

There is no Monkey Patching with this approach. This is the best way to extend JavScript Math. There is no need to repeat the explanations from the other answers.