An extension of ES6 Promises that allows for easier deferred resolution/rejection

deferred.js

export class Deferred extends Promise {
  constructor(executor) {
    super( (resolve, reject) => {
      this.resolve = resolve;
      this.reject = reject;
      if (executor) executor(resolve, reject);
    });
  }
}

looks like there's no access to this before super(), so this seems to be about as terse as you can go: https://github.com/tj/deferred.js/blob/master/index.js