event emitter synchronous node.js client side

Question

event emitter synchronous node.js client side

function findById(id) {
    var fullName = "";
    client.emit("findById", id, function(result){
        fullName = result.fullName;
    });
}

I want find full name from function findById

When I call function findById result = ""

javascript
node.js

Answer 1

To make it synchronous, you have to lock up the function with a loop. I don't recommend doing this.

function findById(id) {
   var fullname, waiting = true;

   client.emit("findById", id, function(result){
       fullname = result.fullName;
       waiting  = false;
   });

   while (waiting);
   return fullname;
}

It's better to just embrace the fact the method is inherently asynchronous, and pass the result to a callback:

function findById(id, callback) {
   client.emit("findById", id, function(result){
       callback(result.fullName);
   });
}

Usage would then be:

findById(id, function(fullName) { /* ... */ });

If nested callbacks become a headache in your application, there are flow control libraries like async (runs in Node and in the browser) that make things cleaner and more readable.