Thens 🕺🏻 🕺🏻 🕺🏻

The instrument to create async functions sequence, powered by Promise. It is Promise.then in the plural.

Forget about Promise.resolve, or new Promise, or then.then.then chain. Just compose functions and await result. Or use it as handler for native then, or a part of thens. And don't forget it supports generators.

Enjoy.

yarn add thens

Usage.

import thens from 'thens';

const calc = thens(
  // Static
  a => a + 1, 
  // Async like
  b => Promise.resolve(b + 1),
  // Real async
  c => new Promise((resolve) => setTimeout(() => resolve(c + 1))),
  // Like Promise.all
  [
    d => d + 1,
    d => Promise.resolve(d + 2),
    d => new Promise((resolve) => setTimeout(() => resolve(d + 3))),
  ],
  // Generator, driven by rebound runner
  function* ([e, f, g]) {
    // Async inside generator
    const h = yield Promise.resolve(e + f + g);
    try {
      throw new Error('Unexpected error');
    } catch(e) {
      // Error handler inside generator
      return h;
    }
  }
);

calc(0)
.then(console.log) // 15
.catch(console.warn); // And don't forget to add final catch

License

MIT, 2017, Vladimir Kalmykov [email protected]