async generator

async-generator.js

/**
 * 一个异步生成器的简单函数实现
 * 演示参照下方exec
 */
var async = function (makeGenerator) {
  return function () {
    var generator = makeGenerator();
    var continuer = function (result, value) {
      if (result && result.done) {
        return;
      }
      result = generator.next(value);
      if (result.value instanceof Promise) {
        result.value.then((value)=> {
          continuer(result, value);
        });
      } else {
        continuer(result);
      }
    }
    continuer();
  }
}

/* DEMO */

var aPromsieFunction = function () {
  return new Promise( (resolve, reject) => {
    setTimeout(function(){ resolve('resolve1');}, 1000);
  });
}
var anotherPromiseFunction = function () {
  return new Promise( (resolve, reject) => {
    setTimeout(function(){ resolve('resolve2');}, 1000);
  });
}
var exec = async(function* () {
  var r1 = yield aPromsieFunction();
  console.log('r1', r1);
  var r2 = yield anotherPromiseFunction();
  console.log('r2', r2);
});
exec();