js中传统回调函数如何轻松实现asyn/await

Question

As we know, ES6 give us a great solution for callback hell， but how to handle the source which already wrote withe call back? I don't want to rewrite those code, just want to get a easy way to make it works.

Answer 1

1. A helper function

   function promise(this_obj, func, ...restArgs) { return new Promise((resolve, reject) => { restArgs.push((err,result)=>{ if(err){ reject(err); }else{ resolve(result); } }); func.apply (this_obj, restArgs); }); }

2. Before

    redis.hget("k1", "k2", function (err, result) { if (err) { reject(err); } else { resolve(result); } });

3. Now

   var result = await promise(redis, redis.hget, "k1", "k2");