SOURCE CODE: Uize.Util.Dependencies.Async (view docs)

/*______________
|       ______  |   U I Z E    J A V A S C R I P T    F R A M E W O R K
|     /      /  |   ---------------------------------------------------
|    /    O /   |    MODULE : Uize.Util.Dependencies.Async Package
|   /    / /    |
|  /    / /  /| |    ONLINE : http://www.uize.com
| /____/ /__/_| | COPYRIGHT : (c)2013-2016 UIZE
|          /___ |   LICENSE : Available under MIT License or GNU General Public License
|_______________|             http://www.uize.com/license.html
*/

/* Module Meta Data
  type: Package
  importance: 1
  codeCompleteness: 100
  docCompleteness: 100
*/

/*?
  Introduction
    The =Uize.Util.Dependencies.Async= utility module provides methods for working with dependency relationships in a generic way, and where the method for obtaining direct dependencies involves an asynchronous process.

    *DEVELOPERS:* `Chris van Rensburg`

    While the =Uize.Util.Dependencies.Async= module is used by the =Uize.Build.ModuleInfo= build utility module to trace module dependencies, the methods of the =Uize.Util.Dependencies.Async= module are expressed in sufficiently generic terms that the module can be used for many types of items that have dependency relationships.
*/

Uize.module ({
  name:'Uize.Util.Dependencies.Async',
  required:'Uize.Flo',
  builder:function () {
    'use strict';

    /*** General Variables ***/
      var
        _trueFlagValue = {},
        _resolveDependenciesList = Uize.Util.Dependencies.resolveDependenciesList
      ;

    return Uize.package ({
      traceDependencies:function (_rootDependencies,_getDirectDependencies,_excludeDependencies,_callback) {
        var
          _excludeDependenciesLookup = Uize.lookup (
            _resolveDependenciesList (_excludeDependencies),
            _trueFlagValue
          ),
          _dependenciesNeeded = []
        ;
        function _traceDependencies (_dependencies,_next) {
          Uize.Flo.forEach (
            function (_next) {_next (_dependencies.sort ())},
            function (_next) {
              var
                m = this,
                _dependency = m.value
              ;
              m ['if'] (
                function (_next) {_next (_excludeDependenciesLookup [_dependency] != _trueFlagValue)},
                [
                  function (_next) {
                    _excludeDependenciesLookup [_dependency] = _trueFlagValue;
                    _getDirectDependencies (_dependency,_next);
                  },
                  function (_next) {
                    _traceDependencies (this.result,_next);
                  },
                  function (_next) {
                    _dependenciesNeeded.push (_dependency);
                    _next ();
                  }
                ]
              ) (_next);
            }
          ) (_next);
        }
        _traceDependencies (
          _resolveDependenciesList (_rootDependencies),
          function () {_callback (_dependenciesNeeded)}
        );
      }
    });
  }
});