Method Chaining

method-chaining.js

var calculator = function(){
    return this;
}

calculator.prototype.set = function (number){
    if(number === undefined)this.number = Math.floor(Math.random() * 1000);
    else this.number = number;
    return this;
}
calculator.prototype.add = function(number = 0){
    this.number += number;
    return this;
}
calculator.prototype.sub = function(number = 0){
    this.number-= number;
    return this;
}
calculator.prototype.div = function(number = 1){
    this.number/= number;
    return this;
}
calculator.prototype.multi = function(number = 1){
    this.number*= number;
    return this;
}
calculator.prototype.mod = function(number){
    if(number !== undefined)this.number%= number;
    return this;
}
calculator.prototype.get = function(){
    return this.number;
}
calculator.prototype.inc = function(number){
    if(number === undefined)this.number++;
    else this.number +=number;
    return this;
}
calculator.prototype.dec = function(number){
    if(number === undefined)this.number--;
    else this.number -=number;
    return this;
}
console.log(new calculator().set(10).add(10).sub(2).multi(10).div(2).mod(4).inc().inc(2).dec(3).dec().get());