How does VK.api work?

Question

JavaScript

Interested in the moment of initialization. There is an api, it can only be accessed when all modules are loaded. Loading modules is sticking scripts into the header. Hence the question - how can you understand that all the scripts are inserted and you can pull the api?

//Сам инит
My.init = function (callback) {
  if (My.isFunc(callback)) callback();
};

//Вызов апи, когда произошёл инит 
My.init(function(){
   My.api('user', {uid:2}, function(data) {
       console.log(data);
   });
});

//Загрузка модулей
My.loadModule = function (src, callback, appendTo) {
  var script = document.createElement('script');

  if (!appendTo) {
    appendTo = document.getElementsByTagName('head')[0];
  }

  if (script.readyState && !script.onload) {
    // IE, Opera
    script.onreadystatechange = function () {
      if (script.readyState == "loaded" || script.readyState == "complete") {
        script.onreadystatechange = null;
        callback();
      }
    }
  }
  else {
    script.onload = callback;
  }

  script.src = My.domain + '/js/modules/' + src + '.js';
  appendTo.appendChild(script);
};

Here is such a code, in the modules folder there are modules, respectively. How to determine that all scripts are in the header and give the green light to the execution of functions inside My.init(function(){}?

Answer 1

habrahabr.ru/post/182310
As far as I understand, if you connect scripts to work with api after connecting all modules, your script will not start until those above are downloaded and executed. So some kind of callback is not needed in this situation.

Answer 2

Why not write a class for loading scripts, or take something ready.