Node.js - 等待完成多个功能

Question

所以我的代码看起来像:

var data = someobject;

for(var x in data){
    mongo.findOne({ _id:data[x]._id },function(e,post){
        if(post != null){

            post.title = 'omg updated';
            post.save(function(){
                console.log('all done updating');
            });

        }
    });
}

// I need all ^ those functions to be done before continuing to the following function:
some_function();

我已经查看了异步库,当我有一定数量的函数需要在一次运行时,我用它来并行.但我不确定如何达到预期的效果.

所有这些功能都可以并行运行,我只需要知道什么时候完成.

Answer 1

这是Async的forEach方法的完美案例,该方法将对数组的元素执行并行任务,然后调用回调,例如:

async.forEach(Object.keys(data), function doStuff(x, callback) {
  // access the value of the key with with data[x]
  mongo.findOne({ _id:data[x]._id },function(e, post){
    if(post != null){
      post.title = 'omg updated';
      post.save(callback);
    }
  });  
}, function(err){
  // if any of the saves produced an error, err would equal that error
});