在nodejs中，函数会在函数内的所有回调执行之前返回吗？

Question

  function A (req,res){
   db.query(sql,cb(err,results){
      //do something
   }
}

When I call function A in the code shown above, will it return before the cb has executed?

Answer 1

Not necessarily. If db.query is actually asynchronous, then the answer is yes. However, many functions with callback-style signatures are not actually asynchronous, so it is possible that cb will run before A returns. You should not count on either order of events in general.

Answer 2

Yes.

You can use async to control you sync flow.