Simple chaining

main.js

    // Chaining pattern
    var main = {
        index: 10,
        addToIndex: function () {
            this.index += 10;
            return this; // return instance of the object and allow chaining
        },
        subtractFromIndex: function () {
            this.index -= 10;
            return this; // return instance of the object and allow chaining
        }
    };
    console.log(main.addToIndex().subtractFromIndex());