https://repl.it/LBrp/3

LBrp-3.js

const proto = {
  timeout: null,
  promise: null,
  racer: null,
  then(fn) {
    this.promise = this.promise.then(result => {
      return Promise.race([this.racer, fn(result)]);
    });

    return this;
  },
  run(fn) {
    this.promise = this.promise.then(fn, fn);
    return this;
  },
  catch(fn) {
    this.promise = this.promise.catch(fn);
    return this;
  },
  end() {
    this.promise.then(() => {
      clearTimeout(this.timeout);
    })
    
    return this.promise;
  }
};

const chainer = time => {
  let timeout;

  return fn => {
    const racer = new Promise((res, rej) => {
      timeout = setTimeout(() => {
        console.log('finished');
        rej(new Error('TIME_OUT'));
      }, time);
    });

    return Object.assign(Object.create(proto), {
      timeout,
      racer,
      promise: Promise.race([racer, fn()]),
    });
  };
};


// *********
//  EXAMPLE
// *********
chainer(1000)(() => {
  return new Promise(res => {
    setTimeout(() => res('hello'), 100);
  });
})
  .then(s => {
    console.log(s);
    return new Promise(res => {
      setTimeout(() => {
        res('coucou');
      }, 2000);
    });
  })
  .then(s => {
    console.log(s);
    return new Promise(res => {
      setTimeout(() => {
        res('coucou2');
        console.log('coucou2');
      }, 2000);
    });
  })
  .run(() => {
    // runs anyway
    console.log('runs anyway')
    return 'runs'
  })
  .catch(err => {
    console.log('coucou error: ', err);
  })
  .end()
  .then(res => {
    console.log('after chainer ends you get the real promise behind')
    console.log(res);
  });