Chaining

by fredericklim

JavaScript

let ladder = {
  step: 0,
  up() {
    this.step++;
    return this;
  },
  down() {
    this.step--;
    return this;
  },
  showStep: function() { // shows the current step
    alert( this.step );
  }
};

ladder.up().up().down().up().down().showStep();