generator2promise

Transform generator to promise

Usage

Wrap the generator function yield a function that can return a Promise.

const g2p = require('g2p');
const func = g2p(function*() {
  return yield Promise.resolve('done');
});

func()
.then(function(val) {
  console.log(val); // => done
})

You can bind the context and pass argument.

const g2p = require('g2p');
const ctx = { key: 'done' };
const func = g2p(function*(val) {
  return this.key + val;
}, ctx);

func('done')
.then(function(val) {
  console.log(val); // => donedone
})

You can't yield another generator function or thunk in the wrapped generator function.

Why?

If you have ever used co, and it's same as co.wrap. But it's simple for the future, it desugers from the async function.

async function will return a promise after calling, same as g2p. and always await a promise, not thunk or generator function. If you write code follow this, you can easily use async/await after it releases.

Write you API in generator function and wrap it with g2p.

// lib/index.js
exports.test = function*() {
  return yield promise;
};

// index.js
const g2p = require('g2p');
const lib = require('./lib');
exports.test = g2p(lib.test, lib);

Make sure modules that you depend on always return promise

If it's a generator function, you can use g2p.

If it's a thunk, you can wrap it with co.

If it's a callback, you can wrap it with co.

You can also wrap thunk or callback by yourself, leave co alone.