How to get response from asynchronous function?

Question

JavaScript

function AppCreate(data) {
  window.WebViewJavascriptBridge.callHandler('create', data, function(response) {
    return response
  })
}

Actually, how to get a response by calling AppCreate ()?

Answer 1

Well, the best thing is to use callback.

function AppCreate(data, callback) {
  window.WebViewJavascriptBridge.callHandler('create', data, function(response) {
    callback(response);
    return response;
  })
}
AppCreate(data, function(response){
  // здесь что-то делать с response
});

But this is how Callback Hall will start soon, so we came up with such a cute lib like Q (provises)
https://github.com/kriskowal/q
UPD:

function AppCreate(data) {
     var deferred = Q.defer();
      window.WebViewJavascriptBridge.callHandler('create', data, function(response) {
           deferred.resolve(data);
     });
    return response;
}

AppCreate(data).then(function(response){
  // здесь что-то делать с response
});

The difference is that your request does not know anything about how its result will be processed. It only promises to return data, and returns it. No callbacks need to be passed inside the request

Answer 2

If the function is asynchronous, then you won’t be able to get the value except through callbacks, and promises are also a kind of callbacks, only implemented in a more convenient way