neuronjs/lib/define.js

Neuron is A Full Feature CommonJS Module Manager, Dependency Graph Handler and Loader for Browsers

// module define
// ---------------------------------------------------------------------------------------------------


// Method to define a module.

// **NOTICE** that `define` has no fault tolerance and type checking since neuron 2.0,
// because `define` method is no longer designed for human developers to use directly.
// `define` should be generated by some develop environment such as [cortex](http://github.com/cortexjs/cortex)
// @private

// @param {string} id (optional) module identifier
// @param {Array.<string>} dependencies ATTENSION! `dependencies` must be array of standard 
//   module id and there will be NO fault tolerance for argument `dependencies`. Be carefull!
// @param {function(...[*])} factory (require, exports, module)
// @param {Object=} options

// @return {undefined}
function define(id, dependencies, factory, options) {
  options || (options = {});

  var parsed = parse_id(id);
  if (parsed.p) {
    // Legacy
    // in old times, main entry: 
    // - define(id_without_ext)
    // - define(pkg) <- even older
    // now, main entry: define(id_with_ext)
    // parsed.p = legacy_transform_id(parsed.p, options);
    format_parsed(parsed);
  }
  
  var pkg = parsed.k;
  var modMain;
  if (options.main) {
    modMain = mods[pkg];
  }

  // `mod['a@1.1.0']` must be USED before `mod['a@1.1.0/index.js']`,
  // because nobody knows which module is the main entry of 'a@1.1.0'
  // But `mod['a@1.1.0/index.js']` might be DEFINED first.
  var mod = mods[parsed.id] = modMain || mods[parsed.id] || get_mod(parsed);
  if (options.main) {
    mods[pkg] = mod;
    // Set the real id and path
    mix(mod, parsed);
  }
  mix(mod, options);

  // A single module might be defined more than once.
  // use this trick to prevent module redefining, avoiding the subsequent side effect.
  // mod.factory        -> already defined
  // X mod.exports  -> the module initialization is done
  if (!mod.factory) {
    mod.factory = factory;
    mod.deps = dependencies;
    // ['a@0.0.1']  -> {'a' -> 'a@0.0.1'}
    generate_module_version_map(dependencies, mod.m);

    run_callbacks(mod, 'l');
  }
}


// @private
// create version info of the dependencies of current module into current sandbox
// @param {Array.<string>} modules no type detecting
// @param {Object} host

// ['a@~0.1.0', 'b@~2.3.9']
// -> 
// {
//     a: '~0.1.0',
//     b: '~2.3.9'
// }
function generate_module_version_map(modules, host) {
  modules.forEach(function(mod) {
    var name = mod.split('@')[0];
    host[name] = mod;
  });
}


// Run the callbacks
function run_callbacks (object, key) {
  var callbacks = object[key];
  var callback;
  // Mark the module is ready
  // `delete module.c` is not safe
  // #135
  // Android 2.2 might treat `null` as [object Global] and equal it to true,
  // So, never confuse `null` and `false`
  object[key] = FALSE;
  while(callback = callbacks.pop()){
    callback();
  }
}