this.js

const f = () => {
  return {
    process() {
      return Promise.resolve().then(this.other);  // Cannot read property 'last' of undefined
      return Promise.resolve().then(this.other.bind(this));  // WORKS
      return Promise.resolve().then( () => this.other() );   // WORKS
     },
    other() {
      return this.last();
    },
    last() {
      return console.log('hey');
    }
  };
};

f().process();