A simple way of chaining methods

chainable-methods.js

class klass {
  constructor() {}

  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;
  }

  pipe(method) {
    this.value = method(this.value);

    return this;
  }

  log() {
    console.log('klass.value: ', this.value);

    return this;
  }
}

new klass()
  .sum(1, 2, 3) // 6
  .add(10) // 16
  .pipe(val => {
    return val + 1;
  }) // 17
  .subtract(5)
  .log(); // 12