我从model.find（）的返回函数中得到了未定义

Question

Here is my function that I want to return

var setUser = function(Email){
   UserModel.findOne({email : Email}, function(err, data){
      if(err) {
          return Hapi.error.badRequest('There is no this user');
      }
      console.log(data);
      return data;
   });
};

The console.log(data); show the result that found. But When I use this function

Example

console.log(setUser('123@mail.com'));

This log got undefined that returned from function. But log in the function had data.

Answer 1

.findOne executes asynchronously and you can't return from the callback function ... that won't go anywhere. Instead you would need to do something like:

setUser('123@mail.com', console.log)

var setUser = function (Email, callback) {
        // .. snip
        callback(data);
}