better promise

betterpromise.js

/* eslint-disable func-names, no-extend-native */

Promise.prototype.catch = function (...args) {
  if (args.length === 0) {
    throw new TypeError('0 arguments given');
  }

  if (typeof args[args.length - 1] !== 'function') {
    throw new TypeError('Last argument must be a function');
  }

  if (args.length === 1) {
    return this.then(undefined, err => args[0](err));
  }

  const errorClasses = args.splice(0, args.length - 2);

  return this.then(undefined, (err) => {
    for (let i = 0; i < errorClasses.length; i += 1) {
      if (err instanceof errorClasses[i]) {
        return args[args.length - 1](err);
      }
    }

    return err;
  });
};

Promise.prototype.tap = function (func) {
  return this.then(func)
    .then(() => this);
};

Promise.resolve(1)
  .tap((d) => console.log('a', d))
  .tap((d) => console.log('a', d))
  .tap((d) => console.log('a', d))
  .tap((d) => console.log('a', d))
  .tap(async () => {
    throw new Error('message');
  })
  .catch((err) => {
    console.log('error', err);
  });