method chaining in javascript
class Arithmetic { constructor() { this.value = 0; } sum(...args) { this.value = args.reduce((sum, current) => sum + current, 0); return this; } add(value) { this.value = this.value + value; return this; } subtract(value) { this.value = this.value - value; return this; } average(...args) { this.value = args.length ? (this.sum(...args).value) / args.length : undefined; return this; } } a = new Arithmetic() a.sum(1, 3, 6) // => { value: 10 } .subtract(3) // => { value: 7 } .add(4) // => { value: 11 } .value // => 11 // Console Output // 11
