async-await-with-generators

Simple implementation of async/await using generators

Usage:

Call run with a generator to start an async flow immediately, use yield instead of await

run(function* () {
  try {
    const res  = yield fetch(`https://api.github.com/repos/facebook/react`);
    const data = yield res.json();
    return data.stargazers_count;
  } catch (err) {
    return `Couldn't get the stars number`;
  }
})
.then((stars) => { ... })

Or, use run.wrap to return a function instead

const getStars = run.wrap(function* (username, repo) {
  try {
    const res  = yield fetch(`https://api.github.com/repos/${username}/${repo}`);
    const data = yield res.json();
    return data.stargazers_count;
  } catch (err) {
    return `Couldn't get the stars number`;
  }
});

getStars('facebook', 'react').then((stars) => { ... })

Implementation:

const next = (it, res, err) => {
  const { value, done } = err ? it.throw(err) : it.next(res);

  if (done) {
    return Promise.resolve(value);
  }

  return Promise.resolve(value)
    .then(res  => next(it, res))
    .catch(err => next(it, null, err));
};

const run = (gen) => next(gen());

run.wrap  = (gen) => (...args) => next(gen(...args));

module.exports = run;