very simple javascript module dependency manager

register-and-callback-when-available.js

// This simple module makes available a UUID generator created by Jeff Ward
//
// This module will be available under the global App.UUID
//
// After this module has completely loaded it registers itself so other modules that
// depend on it being present can wait until it is available to complete their startup.

**
 * Fast UUID generator, RFC4122 version 4 compliant.
 * @author Jeff Ward (jcward.com).
 * @license MIT license
 * @link http://stackoverflow.com/questions/105034/how-to-create-a-guid-uuid-in-javascript/21963136#21963136
 *
 */

(function() {
  jQuery(document).ready(function() {
    App.UUID = (function() {
      var i, lut, self;
      self = {};
      lut = [];
      i = 0;
      while (i < 256) {
        lut[i] = (i < 16 ? '0' : '') + i.toString(16);
        i++;
      }
      self.generate = function() {
        var d0, d1, d2, d3;
        d0 = Math.random() * 0xffffffff | 0;
        d1 = Math.random() * 0xffffffff | 0;
        d2 = Math.random() * 0xffffffff | 0;
        d3 = Math.random() * 0xffffffff | 0;
        return lut[d0 & 0xff] + lut[d0 >> 8 & 0xff] + lut[d0 >> 16 & 0xff] + lut[d0 >> 24 & 0xff] + '-' + lut[d1 & 0xff] + lut[d1 >> 8 & 0xff] + '-' + lut[d1 >> 16 & 0x0f | 0x40] + lut[d1 >> 24 & 0xff] + '-' + lut[d2 & 0x3f | 0x80] + lut[d2 >> 8 & 0xff] + '-' + lut[d2 >> 16 & 0xff] + lut[d2 >> 24 & 0xff] + lut[d3 & 0xff] + lut[d3 >> 8 & 0xff] + lut[d3 >> 16 & 0xff] + lut[d3 >> 24 & 0xff];
      };
      return self;
    })();
    return App.component.register('uuid');
  });

}).call(this);


// In a second module that requires the presence of App.UUID to function
// this function is called after the second module is loaded.
// The function finishSecondModuleSetup() will be called after App.UUID
// has loaded and registered itself.

App.component.callbackWhenAvailable('uuid', finishSecondModuleSetup)


// A very simple App component module system I wrote.
//
// When a JavaScript module has completed loading the module should resister itself:
//
// example: App.component.register('uuid');
//
// If a module depends on the presense of another module before it
// can complete it's startup it can request a callbackWhenAvailable when the
// other module is registered and available.
//
// Example after loading second-module.js: App.component.callbackWhenAvailable('uuid', finishSecondModuleSetup)

(function() {
  (function() {
    this.App || (this.App = {});
    return App.component = (function() {
      var callbackWhenAvailable, components, register, self;
      components = {};
      register = function(component) {
        if (components[component]) {
          if (components[component].registered) {
            return console("*** Component: " + component + " already registered");
          } else {
            components[component].registered = true;
            components[component].callbackWhenAvailables.forEach(function(callbackWhenAvailable) {
              callbackWhenAvailable();
            });
            return components[component].callbackWhenAvailables = [];
          }
        } else {
          components[component] = {};
          components[component].registered = true;
          return components[component].callbackWhenAvailables = [];
        }
      };
      callbackWhenAvailable = function(component, callbackWhenAvailable) {
        if (!components[component]) {
          components[component] = {};
          components[component].callbackWhenAvailables = [];
        }
        if (components[component].registered) {
          return callbackWhenAvailable();
        } else {
          return components[component].callbackWhenAvailables.push(callbackWhenAvailable);
        }
      };
      return self = {
        register: register,
        callbackWhenAvailable: callbackWhenAvailable,
        components: components
      };
    })();
  }).call(this);

}).call(this);