Async in Babel

async-babel.js

"use strict";

function asyncGeneratorStep(gen, resolve, reject, _next, _throw, key, arg) {
  try {
    var info = gen[key](arg);
    var value = info.value;
  } catch (error) {
    reject(error);
    return;
  }
  if (info.done) {
    resolve(value);
  } else {
    console.log(value)
    value.then(_next, _throw);
  }
}

function _asyncToGenerator(fn) {
  return function() {
    var self = this,
      args = arguments;
    return new Promise(function(resolve, reject) {
      var gen = fn.apply(self, args);
      function _next(value) {
        console.log("next",value)
        asyncGeneratorStep(gen, resolve, reject, _next, _throw, "next", value);
      }
      function _throw(err) {
        console.log("throw",err)
        asyncGeneratorStep(gen, resolve, reject, _next, _throw, "throw", err);
      }
      _next(undefined);
    });
  };
}

function bar(ms, value) {
  return new Promise((resolve, reject) => {
    setTimeout(() => resolve(value), ms);
  });
}

function foo() {
  return _foo.apply(this, arguments);
}

function _foo() {
  _foo = _asyncToGenerator(function*() {
    let b = yield bar(500, "first");
    console.log(b);
    b = yield bar(2000, "second");
    console.log(b);
  });
  return _foo.apply(this, arguments);
}

foo()