es6-module-loader-dev.src.js

(function(__global) {

  var isWorker = typeof window == 'undefined' && typeof self != 'undefined' && typeof importScripts != 'undefined';
  var isBrowser = typeof window != 'undefined' && typeof document != 'undefined';
  var isWindows = typeof process != 'undefined' && !!process.platform.match(/^win/);

  if (!__global.console)
    __global.console = { assert: function() {} };

  // IE8 support
  var indexOf = Array.prototype.indexOf || function(item) {
    for (var i = 0, thisLen = this.length; i < thisLen; i++) {
      if (this[i] === item) {
        return i;
      }
    }
    return -1;
  };
  
  var defineProperty;
  (function () {
    try {
      if (!!Object.defineProperty({}, 'a', {}))
        defineProperty = Object.defineProperty;
    }
    catch (e) {
      defineProperty = function(obj, prop, opt) {
        try {
          obj[prop] = opt.value || opt.get.call(obj);
        }
        catch(e) {}
      }
    }
  })();

  function addToError(err, msg) {
    var newErr;
    if (err instanceof Error) {
      var newErr = new Error(err.message, err.fileName, err.lineNumber);
      newErr.message = err.message + '\n\t' + msg;
      newErr.stack = err.stack;
    }
    else {
      newErr = err + '\n\t' + msg;
    }
      
    return newErr;
  }

  function __eval(source, debugName, context) {
    try {
      new Function(source).call(context);
    }
    catch(e) {
      throw addToError(e, 'Evaluating ' + debugName);
    }
  }

  var baseURI;
  // environent baseURI detection
  if (typeof document != 'undefined' && document.getElementsByTagName) {
    baseURI = document.baseURI;

    if (!baseURI) {
      var bases = document.getElementsByTagName('base');
      baseURI = bases[0] && bases[0].href || window.location.href;
    }

    // sanitize out the hash and querystring
    baseURI = baseURI.split('#')[0].split('?')[0];
    baseURI = baseURI.substr(0, baseURI.lastIndexOf('/') + 1);
  }
  else if (typeof process != 'undefined' && process.cwd) {
    baseURI = 'file://' + (isWindows ? '/' : '') + process.cwd() + '/';
    if (isWindows)
      baseURI = baseURI.replace(/\\/g, '/');
  }
  else if (typeof location != 'undefined') {
    baseURI = __global.location.href;
  }
  else {
    throw new TypeError('No environment baseURI');
  }

  var URL = typeof __global.URL == 'function' && __global.URL || URLPolyfill;

/*
*********************************************************************************************

  Dynamic Module Loader Polyfill

    - Implemented exactly to the former 2014-08-24 ES6 Specification Draft Rev 27, Section 15
      http://wiki.ecmascript.org/doku.php?id=harmony:specification_drafts#august_24_2014_draft_rev_27

    - Functions are commented with their spec numbers, with spec differences commented.

    - Spec bugs are commented in this code with links.

    - Abstract functions have been combined where possible, and their associated functions
      commented.

    - Realm implementation is entirely omitted.

*********************************************************************************************
*/

function Module() {}
function Loader(options) {
  this._loader = {
    loaderObj: this,
    loads: [],
    modules: {},
    importPromises: {},
    moduleRecords: {}
  };

  // 26.3.3.6
  defineProperty(this, 'global', {
    get: function() {
      return __global;
    }
  });

  // 26.3.3.13 realm not implemented
}

(function() {

// Some Helpers

// logs a linkset snapshot for debugging
/* function snapshot(loader) {
  console.log('---Snapshot---');
  for (var i = 0; i < loader.loads.length; i++) {
    var load = loader.loads[i];
    var linkSetLog = '  ' + load.name + ' (' + load.status + '): ';

    for (var j = 0; j < load.linkSets.length; j++) {
      linkSetLog += '{' + logloads(load.linkSets[j].loads) + '} ';
    }
    console.log(linkSetLog);
  }
  console.log('');
}
function logloads(loads) {
  var log = '';
  for (var k = 0; k < loads.length; k++)
    log += loads[k].name + (k != loads.length - 1 ? ' ' : '');
  return log;
} */


/* function checkInvariants() {
  // see https://bugs.ecmascript.org/show_bug.cgi?id=2603#c1

  var loads = System._loader.loads;
  var linkSets = [];

  for (var i = 0; i < loads.length; i++) {
    var load = loads[i];
    console.assert(load.status == 'loading' || load.status == 'loaded', 'Each load is loading or loaded');

    for (var j = 0; j < load.linkSets.length; j++) {
      var linkSet = load.linkSets[j];

      for (var k = 0; k < linkSet.loads.length; k++)
        console.assert(loads.indexOf(linkSet.loads[k]) != -1, 'linkSet loads are a subset of loader loads');

      if (linkSets.indexOf(linkSet) == -1)
        linkSets.push(linkSet);
    }
  }

  for (var i = 0; i < loads.length; i++) {
    var load = loads[i];
    for (var j = 0; j < linkSets.length; j++) {
      var linkSet = linkSets[j];

      if (linkSet.loads.indexOf(load) != -1)
        console.assert(load.linkSets.indexOf(linkSet) != -1, 'linkSet contains load -> load contains linkSet');

      if (load.linkSets.indexOf(linkSet) != -1)
        console.assert(linkSet.loads.indexOf(load) != -1, 'load contains linkSet -> linkSet contains load');
    }
  }

  for (var i = 0; i < linkSets.length; i++) {
    var linkSet = linkSets[i];
    for (var j = 0; j < linkSet.loads.length; j++) {
      var load = linkSet.loads[j];

      for (var k = 0; k < load.dependencies.length; k++) {
        var depName = load.dependencies[k].value;
        var depLoad;
        for (var l = 0; l < loads.length; l++) {
          if (loads[l].name != depName)
            continue;
          depLoad = loads[l];
          break;
        }

        // loading records are allowed not to have their dependencies yet
        // if (load.status != 'loading')
        //  console.assert(depLoad, 'depLoad found');

        // console.assert(linkSet.loads.indexOf(depLoad) != -1, 'linkset contains all dependencies');
      }
    }
  }
} */

  // 15.2.3 - Runtime Semantics: Loader State

  // 15.2.3.11
  function createLoaderLoad(object) {
    return {
      // modules is an object for ES5 implementation
      modules: {},
      loads: [],
      loaderObj: object
    };
  }

  // 15.2.3.2 Load Records and LoadRequest Objects

  // 15.2.3.2.1
  function createLoad(name) {
    return {
      status: 'loading',
      name: name,
      linkSets: [],
      dependencies: [],
      metadata: {}
    };
  }

  // 15.2.3.2.2 createLoadRequestObject, absorbed into calling functions

  // 15.2.4

  // 15.2.4.1
  function loadModule(loader, name, options) {
    return new Promise(asyncStartLoadPartwayThrough({
      step: options.address ? 'fetch' : 'locate',
      loader: loader,
      moduleName: name,
      // allow metadata for import https://bugs.ecmascript.org/show_bug.cgi?id=3091
      moduleMetadata: options && options.metadata || {},
      moduleSource: options.source,
      moduleAddress: options.address
    }));
  }

  // 15.2.4.2
  function requestLoad(loader, request, refererName, refererAddress) {
    // 15.2.4.2.1 CallNormalize
    return new Promise(function(resolve, reject) {
      resolve(loader.loaderObj.normalize(request, refererName, refererAddress));
    })
    // 15.2.4.2.2 GetOrCreateLoad
    .then(function(name) {
      var load;
      if (loader.modules[name]) {
        load = createLoad(name);
        load.status = 'linked';
        // https://bugs.ecmascript.org/show_bug.cgi?id=2795
        load.module = loader.modules[name];
        return load;
      }

      for (var i = 0, l = loader.loads.length; i < l; i++) {
        load = loader.loads[i];
        if (load.name != name)
          continue;
        console.assert(load.status == 'loading' || load.status == 'loaded', 'loading or loaded');
        return load;
      }

      load = createLoad(name);
      loader.loads.push(load);

      proceedToLocate(loader, load);

      return load;
    });
  }

  // 15.2.4.3
  function proceedToLocate(loader, load) {
    proceedToFetch(loader, load,
      Promise.resolve()
      // 15.2.4.3.1 CallLocate
      .then(function() {
        return loader.loaderObj.locate({ name: load.name, metadata: load.metadata });
      })
    );
  }

  // 15.2.4.4
  function proceedToFetch(loader, load, p) {
    proceedToTranslate(loader, load,
      p
      // 15.2.4.4.1 CallFetch
      .then(function(address) {
        // adjusted, see https://bugs.ecmascript.org/show_bug.cgi?id=2602
        if (load.status != 'loading')
          return;
        load.address = address;

        return loader.loaderObj.fetch({ name: load.name, metadata: load.metadata, address: address });
      })
    );
  }

  var anonCnt = 0;

  // 15.2.4.5
  function proceedToTranslate(loader, load, p) {
    p
    // 15.2.4.5.1 CallTranslate
    .then(function(source) {
      if (load.status != 'loading')
        return;

      return Promise.resolve(loader.loaderObj.translate({ name: load.name, metadata: load.metadata, address: load.address, source: source }))

      // 15.2.4.5.2 CallInstantiate
      .then(function(source) {
        load.source = source;
        return loader.loaderObj.instantiate({ name: load.name, metadata: load.metadata, address: load.address, source: source });
      })

      // 15.2.4.5.3 InstantiateSucceeded
      .then(function(instantiateResult) {
        if (instantiateResult === undefined) {
          load.address = load.address || '<Anonymous Module ' + ++anonCnt + '>';

          // instead of load.kind, use load.isDeclarative
          load.isDeclarative = true;
          return transpile.call(loader.loaderObj, load)
          .then(function(transpiled) {
            // Hijack System.register to set declare function
            var curSystem = __global.System;
            var curRegister = curSystem.register;
            curSystem.register = function(name, deps, declare) {
              if (typeof name != 'string') {
                declare = deps;
                deps = name;
              }
              // store the registered declaration as load.declare
              // store the deps as load.deps
              load.declare = declare;
              load.depsList = deps;
            }
            // empty {} context is closest to undefined 'this' we can get
            __eval(transpiled, load.address, {});
            curSystem.register = curRegister;
          });
        }
        else if (typeof instantiateResult == 'object') {
          load.depsList = instantiateResult.deps || [];
          load.execute = instantiateResult.execute;
          load.isDeclarative = false;
        }
        else
          throw TypeError('Invalid instantiate return value');
      })
      // 15.2.4.6 ProcessLoadDependencies
      .then(function() {
        load.dependencies = [];
        var depsList = load.depsList;

        var loadPromises = [];
        for (var i = 0, l = depsList.length; i < l; i++) (function(request, index) {
          loadPromises.push(
            requestLoad(loader, request, load.name, load.address)

            // 15.2.4.6.1 AddDependencyLoad (load is parentLoad)
            .then(function(depLoad) {

              // adjusted from spec to maintain dependency order
              // this is due to the System.register internal implementation needs
              load.dependencies[index] = {
                key: request,
                value: depLoad.name
              };

              if (depLoad.status != 'linked') {
                var linkSets = load.linkSets.concat([]);
                for (var i = 0, l = linkSets.length; i < l; i++)
                  addLoadToLinkSet(linkSets[i], depLoad);
              }

              // console.log('AddDependencyLoad ' + depLoad.name + ' for ' + load.name);
              // snapshot(loader);
            })
          );
        })(depsList[i], i);

        return Promise.all(loadPromises);
      })

      // 15.2.4.6.2 LoadSucceeded
      .then(function() {
        // console.log('LoadSucceeded ' + load.name);
        // snapshot(loader);

        console.assert(load.status == 'loading', 'is loading');

        load.status = 'loaded';

        var linkSets = load.linkSets.concat([]);
        for (var i = 0, l = linkSets.length; i < l; i++)
          updateLinkSetOnLoad(linkSets[i], load);
      });
    })
    // 15.2.4.5.4 LoadFailed
    ['catch'](function(exc) {
      load.status = 'failed';
      load.exception = exc;

      var linkSets = load.linkSets.concat([]);
      for (var i = 0, l = linkSets.length; i < l; i++) {
        linkSetFailed(linkSets[i], load, exc);
      }

      console.assert(load.linkSets.length == 0, 'linkSets not removed');
    });
  }

  // 15.2.4.7 PromiseOfStartLoadPartwayThrough absorbed into calling functions

  // 15.2.4.7.1
  function asyncStartLoadPartwayThrough(stepState) {
    return function(resolve, reject) {
      var loader = stepState.loader;
      var name = stepState.moduleName;
      var step = stepState.step;

      if (loader.modules[name])
        throw new TypeError('"' + name + '" already exists in the module table');

      // adjusted to pick up existing loads
      var existingLoad;
      for (var i = 0, l = loader.loads.length; i < l; i++) {
        if (loader.loads[i].name == name) {
          existingLoad = loader.loads[i];

          if(step == 'translate' && !existingLoad.source) {
            existingLoad.address = stepState.moduleAddress;
            proceedToTranslate(loader, existingLoad, Promise.resolve(stepState.moduleSource));
          }

          return existingLoad.linkSets[0].done.then(function() {
            resolve(existingLoad);
          });
        }
      }

      var load = createLoad(name);

      load.metadata = stepState.moduleMetadata;

      var linkSet = createLinkSet(loader, load);

      loader.loads.push(load);

      resolve(linkSet.done);

      if (step == 'locate')
        proceedToLocate(loader, load);

      else if (step == 'fetch')
        proceedToFetch(loader, load, Promise.resolve(stepState.moduleAddress));

      else {
        console.assert(step == 'translate', 'translate step');
        load.address = stepState.moduleAddress;
        proceedToTranslate(loader, load, Promise.resolve(stepState.moduleSource));
      }
    }
  }

  // Declarative linking functions run through alternative implementation:
  // 15.2.5.1.1 CreateModuleLinkageRecord not implemented
  // 15.2.5.1.2 LookupExport not implemented
  // 15.2.5.1.3 LookupModuleDependency not implemented

  // 15.2.5.2.1
  function createLinkSet(loader, startingLoad) {
    var linkSet = {
      loader: loader,
      loads: [],
      startingLoad: startingLoad, // added see spec bug https://bugs.ecmascript.org/show_bug.cgi?id=2995
      loadingCount: 0
    };
    linkSet.done = new Promise(function(resolve, reject) {
      linkSet.resolve = resolve;
      linkSet.reject = reject;
    });
    addLoadToLinkSet(linkSet, startingLoad);
    return linkSet;
  }
  // 15.2.5.2.2
  function addLoadToLinkSet(linkSet, load) {
    console.assert(load.status == 'loading' || load.status == 'loaded', 'loading or loaded on link set');

    for (var i = 0, l = linkSet.loads.length; i < l; i++)
      if (linkSet.loads[i] == load)
        return;

    linkSet.loads.push(load);
    load.linkSets.push(linkSet);

    // adjustment, see https://bugs.ecmascript.org/show_bug.cgi?id=2603
    if (load.status != 'loaded') {
      linkSet.loadingCount++;
    }

    var loader = linkSet.loader;

    for (var i = 0, l = load.dependencies.length; i < l; i++) {
      var name = load.dependencies[i].value;

      if (loader.modules[name])
        continue;

      for (var j = 0, d = loader.loads.length; j < d; j++) {
        if (loader.loads[j].name != name)
          continue;

        addLoadToLinkSet(linkSet, loader.loads[j]);
        break;
      }
    }
    // console.log('add to linkset ' + load.name);
    // snapshot(linkSet.loader);
  }

  // linking errors can be generic or load-specific
  // this is necessary for debugging info
  function doLink(linkSet) {
    var error = false;
    try {
      link(linkSet, function(load, exc) {
        linkSetFailed(linkSet, load, exc);
        error = true;
      });
    }
    catch(e) {
      linkSetFailed(linkSet, null, e);
      error = true;
    }
    return error;
  }

  // 15.2.5.2.3
  function updateLinkSetOnLoad(linkSet, load) {
    // console.log('update linkset on load ' + load.name);
    // snapshot(linkSet.loader);

    console.assert(load.status == 'loaded' || load.status == 'linked', 'loaded or linked');

    linkSet.loadingCount--;

    if (linkSet.loadingCount > 0)
      return;

    // adjusted for spec bug https://bugs.ecmascript.org/show_bug.cgi?id=2995
    var startingLoad = linkSet.startingLoad;

    // non-executing link variation for loader tracing
    // on the server. Not in spec.
    /***/
    if (linkSet.loader.loaderObj.execute === false) {
      var loads = [].concat(linkSet.loads);
      for (var i = 0, l = loads.length; i < l; i++) {
        var load = loads[i];
        load.module = !load.isDeclarative ? {
          module: _newModule({})
        } : {
          name: load.name,
          module: _newModule({}),
          evaluated: true
        };
        load.status = 'linked';
        finishLoad(linkSet.loader, load);
      }
      return linkSet.resolve(startingLoad);
    }
    /***/

    var abrupt = doLink(linkSet);

    if (abrupt)
      return;

    console.assert(linkSet.loads.length == 0, 'loads cleared');

    linkSet.resolve(startingLoad);
  }

  // 15.2.5.2.4
  function linkSetFailed(linkSet, load, exc) {
    var loader = linkSet.loader;

    if (load) {
      if (load && linkSet.loads[0].name != load.name)
        exc = addToError(exc, 'Error loading ' + load.name + ' from ' + linkSet.loads[0].name);

      if (load)
        exc = addToError(exc, 'Error loading ' + load.name);
    }
    else {
      exc = addToError(exc, 'Error linking ' + linkSet.loads[0].name);
    }


    var loads = linkSet.loads.concat([]);
    for (var i = 0, l = loads.length; i < l; i++) {
      var load = loads[i];

      // store all failed load records
      loader.loaderObj.failed = loader.loaderObj.failed || [];
      if (indexOf.call(loader.loaderObj.failed, load) == -1)
        loader.loaderObj.failed.push(load);

      var linkIndex = indexOf.call(load.linkSets, linkSet);
      console.assert(linkIndex != -1, 'link not present');
      load.linkSets.splice(linkIndex, 1);
      if (load.linkSets.length == 0) {
        var globalLoadsIndex = indexOf.call(linkSet.loader.loads, load);
        if (globalLoadsIndex != -1)
          linkSet.loader.loads.splice(globalLoadsIndex, 1);
      }
    }
    linkSet.reject(exc);
  }

  // 15.2.5.2.5
  function finishLoad(loader, load) {
    // add to global trace if tracing
    if (loader.loaderObj.trace) {
      if (!loader.loaderObj.loads)
        loader.loaderObj.loads = {};
      var depMap = {};
      load.dependencies.forEach(function(dep) {
        depMap[dep.key] = dep.value;
      });
      loader.loaderObj.loads[load.name] = {
        name: load.name,
        deps: load.dependencies.map(function(dep){ return dep.key }),
        depMap: depMap,
        address: load.address,
        metadata: load.metadata,
        source: load.source,
        kind: load.isDeclarative ? 'declarative' : 'dynamic'
      };
    }
    // if not anonymous, add to the module table
    if (load.name) {
      console.assert(!loader.modules[load.name], 'load not in module table');
      loader.modules[load.name] = load.module;
    }
    var loadIndex = indexOf.call(loader.loads, load);
    if (loadIndex != -1)
      loader.loads.splice(loadIndex, 1);
    for (var i = 0, l = load.linkSets.length; i < l; i++) {
      loadIndex = indexOf.call(load.linkSets[i].loads, load);
      if (loadIndex != -1)
        load.linkSets[i].loads.splice(loadIndex, 1);
    }
    load.linkSets.splice(0, load.linkSets.length);
  }

  function doDynamicExecute(linkSet, load, linkError) {
    try {
      var module = load.execute();
    }
    catch(e) {
      linkError(load, e);
      return;
    }
    if (!module || !(module instanceof Module))
      linkError(load, new TypeError('Execution must define a Module instance'));
    else
      return module;
  }

  // 26.3 Loader

  // 26.3.1.1
  // defined at top

  // importPromises adds ability to import a module twice without error - https://bugs.ecmascript.org/show_bug.cgi?id=2601
  function createImportPromise(loader, name, promise) {
    var importPromises = loader._loader.importPromises;
    return importPromises[name] = promise.then(function(m) {
      importPromises[name] = undefined;
      return m;
    }, function(e) {
      importPromises[name] = undefined;
      throw e;
    });
  }

  Loader.prototype = {
    // 26.3.3.1
    constructor: Loader,
    // 26.3.3.2
    define: function(name, source, options) {
      // check if already defined
      if (this._loader.importPromises[name])
        throw new TypeError('Module is already loading.');
      return createImportPromise(this, name, new Promise(asyncStartLoadPartwayThrough({
        step: 'translate',
        loader: this._loader,
        moduleName: name,
        moduleMetadata: options && options.metadata || {},
        moduleSource: source,
        moduleAddress: options && options.address
      })));
    },
    // 26.3.3.3
    'delete': function(name) {
      var loader = this._loader;
      delete loader.importPromises[name];
      delete loader.moduleRecords[name];
      return loader.modules[name] ? delete loader.modules[name] : false;
    },
    // 26.3.3.4 entries not implemented
    // 26.3.3.5
    get: function(key) {
      if (!this._loader.modules[key])
        return;
      doEnsureEvaluated(this._loader.modules[key], [], this);
      return this._loader.modules[key].module;
    },
    // 26.3.3.7
    has: function(name) {
      return !!this._loader.modules[name];
    },
    // 26.3.3.8
    'import': function(name, parentName, parentAddress) {
      if (typeof parentName == 'object')
        parentName = parentName.name;

      // run normalize first
      var loaderObj = this;

      // added, see https://bugs.ecmascript.org/show_bug.cgi?id=2659
      return Promise.resolve(loaderObj.normalize(name, parentName))
      .then(function(name) {
        var loader = loaderObj._loader;

        if (loader.modules[name]) {
          doEnsureEvaluated(loader.modules[name], [], loader._loader);
          return loader.modules[name].module;
        }

        return loader.importPromises[name] || createImportPromise(loaderObj, name,
          loadModule(loader, name, {})
          .then(function(load) {
            delete loader.importPromises[name];
            return evaluateLoadedModule(loader, load);
          }));
      });
    },
    // 26.3.3.9 keys not implemented
    // 26.3.3.10
    load: function(name, options) {
      if (this._loader.modules[name]) {
        doEnsureEvaluated(this._loader.modules[name], [], this._loader);
        return Promise.resolve(this._loader.modules[name].module);
      }
      return this._loader.importPromises[name] || createImportPromise(this, name, loadModule(this._loader, name, {}));
    },
    // 26.3.3.11
    module: function(source, options) {
      var load = createLoad();
      load.address = options && options.address;
      var linkSet = createLinkSet(this._loader, load);
      var sourcePromise = Promise.resolve(source);
      var loader = this._loader;
      var p = linkSet.done.then(function() {
        return evaluateLoadedModule(loader, load);
      });
      proceedToTranslate(loader, load, sourcePromise);
      return p;
    },
    // 26.3.3.12
    newModule: function (obj) {
      if (typeof obj != 'object')
        throw new TypeError('Expected object');

      // we do this to be able to tell if a module is a module privately in ES5
      // by doing m instanceof Module
      var m = new Module();

      var pNames;
      if (Object.getOwnPropertyNames && obj != null) {
        pNames = Object.getOwnPropertyNames(obj);
      }
      else {
        pNames = [];
        for (var key in obj)
          pNames.push(key);
      }

      for (var i = 0; i < pNames.length; i++) (function(key) {
        defineProperty(m, key, {
          configurable: false,
          enumerable: true,
          get: function () {
            return obj[key];
          }
        });
      })(pNames[i]);

      if (Object.preventExtensions)
        Object.preventExtensions(m);

      return m;
    },
    // 26.3.3.14
    set: function(name, module) {
      if (!(module instanceof Module))
        throw new TypeError('Loader.set(' + name + ', module) must be a module');
      this._loader.modules[name] = {
        module: module
      };
    },
    // 26.3.3.15 values not implemented
    // 26.3.3.16 @@iterator not implemented
    // 26.3.3.17 @@toStringTag not implemented

    // 26.3.3.18.1
    normalize: function(name, referrerName, referrerAddress) {
      return name;
    },
    // 26.3.3.18.2
    locate: function(load) {
      return load.name;
    },
    // 26.3.3.18.3
    fetch: function(load) {
    },
    // 26.3.3.18.4
    translate: function(load) {
      return load.source;
    },
    // 26.3.3.18.5
    instantiate: function(load) {
    }
  };

  var _newModule = Loader.prototype.newModule;

/*
 * ES6 Module Declarative Linking Code - Dev Build Only
 */

  // 15.2.5.3 Module Linking Groups

  // 15.2.5.3.2 BuildLinkageGroups alternative implementation
  // Adjustments (also see https://bugs.ecmascript.org/show_bug.cgi?id=2755)
  // 1. groups is an already-interleaved array of group kinds
  // 2. load.groupIndex is set when this function runs
  // 3. load.groupIndex is the interleaved index ie 0 declarative, 1 dynamic, 2 declarative, ... (or starting with dynamic)
  function buildLinkageGroups(load, loads, groups) {
    groups[load.groupIndex] = groups[load.groupIndex] || [];

    // if the load already has a group index and its in its group, its already been done
    // this logic naturally handles cycles
    if (indexOf.call(groups[load.groupIndex], load) != -1)
      return;

    // now add it to the group to indicate its been seen
    groups[load.groupIndex].push(load);

    for (var i = 0, l = loads.length; i < l; i++) {
      var loadDep = loads[i];

      // dependencies not found are already linked
      for (var j = 0; j < load.dependencies.length; j++) {
        if (loadDep.name == load.dependencies[j].value) {
          // by definition all loads in linkset are loaded, not linked
          console.assert(loadDep.status == 'loaded', 'Load in linkSet not loaded!');

          // if it is a group transition, the index of the dependency has gone up
          // otherwise it is the same as the parent
          var loadDepGroupIndex = load.groupIndex + (loadDep.isDeclarative != load.isDeclarative);

          // the group index of an entry is always the maximum
          if (loadDep.groupIndex === undefined || loadDep.groupIndex < loadDepGroupIndex) {

            // if already in a group, remove from the old group
            if (loadDep.groupIndex !== undefined) {
              groups[loadDep.groupIndex].splice(indexOf.call(groups[loadDep.groupIndex], loadDep), 1);

              // if the old group is empty, then we have a mixed depndency cycle
              if (groups[loadDep.groupIndex].length == 0)
                throw new TypeError("Mixed dependency cycle detected");
            }

            loadDep.groupIndex = loadDepGroupIndex;
          }

          buildLinkageGroups(loadDep, loads, groups);
        }
      }
    }
  }

  // 15.2.5.4
  // declarative linking implementation
  function link(linkSet, linkError) {

    var loader = linkSet.loader;

    if (!linkSet.loads.length)
      return;

    // console.log('linking {' + logloads(linkSet.loads) + '}');
    // snapshot(loader);

    // 15.2.5.3.1 LinkageGroups alternative implementation

    // build all the groups
    // because the first load represents the top of the tree
    // for a given linkset, we can work down from there
    var groups = [];
    var startingLoad = linkSet.loads[0];
    startingLoad.groupIndex = 0;
    buildLinkageGroups(startingLoad, linkSet.loads, groups);

    // determine the kind of the bottom group
    var curGroupDeclarative = startingLoad.isDeclarative == groups.length % 2;

    // run through the groups from bottom to top
    for (var i = groups.length - 1; i >= 0; i--) {
      var group = groups[i];
      for (var j = 0; j < group.length; j++) {
        var load = group[j];

        // 15.2.5.5 LinkDeclarativeModules adjusted
        if (curGroupDeclarative) {
          linkDeclarativeModule(load, linkSet.loads, loader);
        }
        // 15.2.5.6 LinkDynamicModules adjusted
        else {
          var module = doDynamicExecute(linkSet, load, linkError);
          if (!module)
            return;
          load.module = {
            name: load.name,
            module: module
          };
          load.status = 'linked';
        }
        finishLoad(loader, load);
      }

      // alternative current kind for next loop
      curGroupDeclarative = !curGroupDeclarative;
    }
  }


  // custom module records for binding graph
  // store linking module records in a separate table
  function getOrCreateModuleRecord(name, loader) {
    var moduleRecords = loader.moduleRecords;
    return moduleRecords[name] || (moduleRecords[name] = {
      name: name,
      dependencies: [],
      module: new Module(), // start from an empty module and extend
      importers: []
    });
  }

  // custom declarative linking function
  function linkDeclarativeModule(load, loads, loader) {
    if (load.module)
      return;

    var module = load.module = getOrCreateModuleRecord(load.name, loader);
    var moduleObj = load.module.module;

    var registryEntry = load.declare.call(__global, function(name, value) {
      // NB This should be an Object.defineProperty, but that is very slow.
      //    By disaling this module write-protection we gain performance.
      //    It could be useful to allow an option to enable or disable this.
      module.locked = true;
      moduleObj[name] = value;

      for (var i = 0, l = module.importers.length; i < l; i++) {
        var importerModule = module.importers[i];
        if (!importerModule.locked) {
          for (var j = 0; j < importerModule.dependencies.length; ++j) {
            if (importerModule.dependencies[j] === module) {
              importerModule.setters[j](moduleObj);
            }
          }
        }
      }

      module.locked = false;
      return value;
    });

    // setup our setters and execution function
    module.setters = registryEntry.setters;
    module.execute = registryEntry.execute;

    // now link all the module dependencies
    // amending the depMap as we go
    for (var i = 0, l = load.dependencies.length; i < l; i++) {
      var depName = load.dependencies[i].value;
      var depModule = loader.modules[depName];

      // if dependency not already in the module registry
      // then try and link it now
      if (!depModule) {
        // get the dependency load record
        for (var j = 0; j < loads.length; j++) {
          if (loads[j].name != depName)
            continue;

          // only link if already not already started linking (stops at circular / dynamic)
          if (!loads[j].module) {
            linkDeclarativeModule(loads[j], loads, loader);
            depModule = loads[j].module;
          }
          // if circular, create the module record
          else {
            depModule = getOrCreateModuleRecord(depName, loader);
          }
        }
      }

      // only declarative modules have dynamic bindings
      if (depModule.importers) {
        module.dependencies.push(depModule);
        depModule.importers.push(module);
      }
      else {
        // track dynamic records as null module records as already linked
        module.dependencies.push(null);
      }

      // run the setter for this dependency
      if (module.setters[i])
        module.setters[i](depModule.module);
    }

    load.status = 'linked';
  }

  /*
   * Module Object non-exotic for ES5:
   *
   * module.module        bound module object
   * module.execute       execution function for module
   * module.dependencies  list of module objects for dependencies
   * See getOrCreateModuleRecord for all properties
   *
   */
  function doExecute(module) {
    try {
      module.execute.call(__global);
    }
    catch(e) {
      return e;
    }
  }

  // 15.2.5.5.1 LinkImports not implemented
  // 15.2.5.7 ResolveExportEntries not implemented
  // 15.2.5.8 ResolveExports not implemented
  // 15.2.5.9 ResolveExport not implemented
  // 15.2.5.10 ResolveImportEntries not implemented

  // 15.2.6.1
  function evaluateLoadedModule(loader, load) {
    console.assert(load.status == 'linked', 'is linked ' + load.name);

    doEnsureEvaluated(load.module, [], loader);
    return load.module.module;
  }

  // propogate execution errors
  // see https://bugs.ecmascript.org/show_bug.cgi?id=2993
  function doEnsureEvaluated(module, seen, loader) {
    var err = ensureEvaluated(module, seen, loader);
    if (err)
      throw err;
  }
  // 15.2.6.2 EnsureEvaluated adjusted
  function ensureEvaluated(module, seen, loader) {
    if (module.evaluated || !module.dependencies)
      return;

    seen.push(module);

    var deps = module.dependencies;
    var err;

    for (var i = 0, l = deps.length; i < l; i++) {
      var dep = deps[i];
      // dynamic dependencies are empty in module.dependencies
      // as they are already linked
      if (!dep)
        continue;
      if (indexOf.call(seen, dep) == -1) {
        err = ensureEvaluated(dep, seen, loader);
        // stop on error, see https://bugs.ecmascript.org/show_bug.cgi?id=2996
        if (err) {
          err = addToError(err, 'Error evaluating ' + dep.name);
          return err;
        }
      }
    }

    if (module.failed)
      return new Error('Module failed execution.');

    if (module.evaluated)
      return;

    module.evaluated = true;
    err = doExecute(module);
    if (err) {
      module.failed = true;
    }
    else if (Object.preventExtensions) {
      // spec variation
      // we don't create a new module here because it was created and ammended
      // we just disable further extensions instead
      Object.preventExtensions(module.module);
    }

    module.execute = undefined;
    return err;
  }
})();

/*
 * Traceur, Babel and TypeScript transpile hook for Loader
 */
var transpile = (function() {

  // use Traceur by default
  Loader.prototype.transpiler = 'traceur';

  function transpile(load) {
    var self = this;

    return Promise.resolve(__global[self.transpiler == 'typescript' ? 'ts' : self.transpiler]
        || (self.pluginLoader || self)['import'](self.transpiler))
    .then(function(transpiler) {
      if (transpiler.__useDefault)
        transpiler = transpiler['default'];

      var transpileFunction;
      if (transpiler.Compiler)
        transpileFunction = traceurTranspile;
      else if (transpiler.createLanguageService)
        transpileFunction = typescriptTranspile;
      else
        transpileFunction = babelTranspile;

      // note __moduleName will be part of the transformer meta in future when we have the spec for this
      return 'var __moduleName = "' + load.name + '";' + transpileFunction.call(self, load, transpiler) + '\n//# sourceURL=' + load.address + '!transpiled';
    });
  };

  function traceurTranspile(load, traceur) {
    var options = this.traceurOptions || {};
    options.modules = 'instantiate';
    options.script = false;
    options.sourceMaps = 'inline';
    options.filename = load.address;
    options.inputSourceMap = load.metadata.sourceMap;
    options.moduleName = false;

    var compiler = new traceur.Compiler(options);

    return doTraceurCompile(load.source, compiler, options.filename);
  }
  function doTraceurCompile(source, compiler, filename) {
    try {
      return compiler.compile(source, filename);
    }
    catch(e) {
      // traceur throws an error array
      throw e[0];
    }
  }

  function babelTranspile(load, babel) {
    var options = this.babelOptions || {};
    options.modules = 'system';
    options.sourceMap = 'inline';
    options.inputSourceMap = load.metadata.sourceMap;
    options.filename = load.address;
    options.code = true;
    options.ast = false;

    return babel.transform(load.source, options).code;
  }

  function typescriptTranspile(load, ts) {
    var options = this.typescriptOptions || {};
    if (options.target === undefined) {
      options.target = ts.ScriptTarget.ES5;
    }
    options.module = ts.ModuleKind.System;
    options.inlineSourceMap = true;

    return ts.transpile(load.source, options, load.address);
  }

  return transpile;
})();

// from https://gist.github.com/Yaffle/1088850
function URLPolyfill(url, baseURL) {
  if (typeof url != 'string')
    throw new TypeError('URL must be a string');
  var m = String(url).replace(/^\s+|\s+$/g, "").match(/^([^:\/?#]+:)?(?:\/\/(?:([^:@\/?#]*)(?::([^:@\/?#]*))?@)?(([^:\/?#]*)(?::(\d*))?))?([^?#]*)(\?[^#]*)?(#[\s\S]*)?/);
  if (!m) {
    throw new RangeError();
  }
  var protocol = m[1] || "";
  var username = m[2] || "";
  var password = m[3] || "";
  var host = m[4] || "";
  var hostname = m[5] || "";
  var port = m[6] || "";
  var pathname = m[7] || "";
  var search = m[8] || "";
  var hash = m[9] || "";
  if (baseURL !== undefined) {
    var base = baseURL instanceof URLPolyfill ? baseURL : new URLPolyfill(baseURL);
    var flag = protocol === "" && host === "" && username === "";
    if (flag && pathname === "" && search === "") {
      search = base.search;
    }
    if (flag && pathname.charAt(0) !== "/") {
      pathname = (pathname !== "" ? (((base.host !== "" || base.username !== "") && base.pathname === "" ? "/" : "") + base.pathname.slice(0, base.pathname.lastIndexOf("/") + 1) + pathname) : base.pathname);
    }
    // dot segments removal
    var output = [];
    pathname.replace(/^(\.\.?(\/|$))+/, "")
      .replace(/\/(\.(\/|$))+/g, "/")
      .replace(/\/\.\.$/, "/../")
      .replace(/\/?[^\/]*/g, function (p) {
        if (p === "/..") {
          output.pop();
        } else {
          output.push(p);
        }
      });
    pathname = output.join("").replace(/^\//, pathname.charAt(0) === "/" ? "/" : "");
    if (flag) {
      port = base.port;
      hostname = base.hostname;
      host = base.host;
      password = base.password;
      username = base.username;
    }
    if (protocol === "") {
      protocol = base.protocol;
    }
  }

  // convert windows file URLs to use /
  if (protocol == 'file:')
    pathname = pathname.replace(/\\/g, '/');

  this.origin = protocol + (protocol !== "" || host !== "" ? "//" : "") + host;
  this.href = protocol + (protocol !== "" || host !== "" ? "//" : "") + (username !== "" ? username + (password !== "" ? ":" + password : "") + "@" : "") + host + pathname + search + hash;
  this.protocol = protocol;
  this.username = username;
  this.password = password;
  this.host = host;
  this.hostname = hostname;
  this.port = port;
  this.pathname = pathname;
  this.search = search;
  this.hash = hash;
}
(typeof self != 'undefined' ? self : global).URLPolyfill = URLPolyfill;
/*
*********************************************************************************************

  System Loader Implementation

    - Implemented to https://github.com/jorendorff/js-loaders/blob/master/browser-loader.js

    - <script type="module"> supported

*********************************************************************************************
*/

var System;

function SystemLoader() {
  Loader.call(this);
  this.paths = {};
}

// NB no specification provided for System.paths, used ideas discussed in https://github.com/jorendorff/js-loaders/issues/25
function applyPaths(loader, name) {
  // most specific (most number of slashes in path) match wins
  var pathMatch = '', wildcard, maxSlashCount = 0;

  // check to see if we have a paths entry
  for (var p in loader.paths) {
    var pathParts = p.split('*');
    if (pathParts.length > 2)
      throw new TypeError('Only one wildcard in a path is permitted');

    // exact path match
    if (pathParts.length == 1) {
      if (name == p) {
        pathMatch = p;
        break;
      }
    }
    // wildcard path match
    else {
      var slashCount = p.split('/').length;
      if (slashCount >= maxSlashCount &&
          name.substr(0, pathParts[0].length) == pathParts[0] &&
          name.substr(name.length - pathParts[1].length) == pathParts[1]) {
            maxSlashCount = slashCount;
            pathMatch = p;
            wildcard = name.substr(pathParts[0].length, name.length - pathParts[1].length - pathParts[0].length);
          }
    }
  }

  var outPath = loader.paths[pathMatch] || name;
  if (wildcard)
    outPath = outPath.replace('*', wildcard);

  return outPath;
}

// inline Object.create-style class extension
function LoaderProto() {}
LoaderProto.prototype = Loader.prototype;
SystemLoader.prototype = new LoaderProto();

var baseURLCache = {};

var absURLRegEx = /^([^\/]+:\/\/|\/)/;

// Normalization with module names as absolute URLs
SystemLoader.prototype.normalize = function(name, parentName, parentAddress) {
  // NB does `import 'file.js'` import relative to the parent name or baseURL?
  //    have assumed that it is baseURL-relative here, but spec may well align with URLs to be the latter
  //    safe option for users is to always use "./file.js" for relative

  // not absolute or relative -> apply paths (what will be sites)
  if (!name.match(absURLRegEx) && name[0] != '.')
    name = new URL(applyPaths(this, name), baseURI).href;
  // apply parent-relative normalization, parentAddress is already normalized
  else
    name = new URL(name, parentName || baseURI).href;

  return name;
};

SystemLoader.prototype.locate = function(load) {
  return load.name;
};


// ensure the transpiler is loaded correctly
SystemLoader.prototype.instantiate = function(load) {
  var self = this;
  return Promise.resolve(self.normalize(self.transpiler))
  .then(function(transpilerNormalized) {
    // load transpiler as a global (avoiding System clobbering)
    if (load.address === transpilerNormalized) {
      return {
        deps: [],
        execute: function() {
          var curSystem = __global.System;
          var curLoader = __global.Reflect.Loader;
          // ensure not detected as CommonJS
          __eval('(function(require,exports,module){' + load.source + '})();', load.address, __global);
          __global.System = curSystem;
          __global.Reflect.Loader = curLoader;
          return self.newModule({ 'default': __global[self.transpiler], __useDefault: true });
        }
      };
    }
  });
};
  var fetchTextFromURL;
  if (typeof XMLHttpRequest != 'undefined') {
    fetchTextFromURL = function(url, fulfill, reject) {
      // percent encode just '#' in urls
      // according to https://github.com/jorendorff/js-loaders/blob/master/browser-loader.js#L238
      // we should encode everything, but it breaks for servers that don't expect it
      // like in (https://github.com/systemjs/systemjs/issues/168)
      if (isBrowser)
        url = url.replace(/#/g, '%23');

      var xhr = new XMLHttpRequest();
      var sameDomain = true;
      var doTimeout = false;
      if (!('withCredentials' in xhr)) {
        // check if same domain
        var domainCheck = /^(\w+:)?\/\/([^\/]+)/.exec(url);
        if (domainCheck) {
          sameDomain = domainCheck[2] === window.location.host;
          if (domainCheck[1])
            sameDomain &= domainCheck[1] === window.location.protocol;
        }
      }
      if (!sameDomain && typeof XDomainRequest != 'undefined') {
        xhr = new XDomainRequest();
        xhr.onload = load;
        xhr.onerror = error;
        xhr.ontimeout = error;
        xhr.onprogress = function() {};
        xhr.timeout = 0;
        doTimeout = true;
      }
      function load() {
        fulfill(xhr.responseText);
      }
      function error() {
        reject(xhr.statusText + ': ' + url || 'XHR error');
      }

      xhr.onreadystatechange = function () {
        if (xhr.readyState === 4) {
          if (xhr.status === 200 || (xhr.status == 0 && xhr.responseText)) {
            load();
          } else {
            error();
          }
        }
      };
      xhr.open("GET", url, true);

      if (doTimeout)
        setTimeout(function() {
          xhr.send();
        }, 0);

      xhr.send(null);
    };
  }
  else if (typeof require != 'undefined') {
    var fs;
    fetchTextFromURL = function(url, fulfill, reject) {
      if (url.substr(0, 8) != 'file:///')
        throw 'Only file URLs of the form file:/// allowed running in Node.';
      fs = fs || require('fs');
      if (isWindows)
        url = url.replace(/\//g, '\\').substr(8);
      else
        url = url.substr(7);
      return fs.readFile(url, function(err, data) {
        if (err)
          return reject(err);
        else
          fulfill(data + '');
      });
    };
  }
  else {
    throw new TypeError('No environment fetch API available.');
  }

  SystemLoader.prototype.fetch = function(load) {
    return new Promise(function(resolve, reject) {
      fetchTextFromURL(load.address, resolve, reject);
    });
  };
(function() {
  // <script type="module"> support
  // allow a data-init function callback once loaded
  if (isBrowser && typeof document.getElementsByTagName != 'undefined') {
    var curScript = document.getElementsByTagName('script');
    curScript = curScript[curScript.length - 1];

    function completed() {
      document.removeEventListener( "DOMContentLoaded", completed, false );
      window.removeEventListener( "load", completed, false );
      ready();
    }

    function ready() {
      var scripts = document.getElementsByTagName('script');
      for (var i = 0; i < scripts.length; i++) {
        var script = scripts[i];
        if (script.type == 'module') {
          var source = script.innerHTML.substr(1);
          // It is important to reference the global System, rather than the one
          // in our closure. We want to ensure that downstream users/libraries
          // can override System w/ custom behavior.
          System.module(source)['catch'](function(err) { setTimeout(function() { throw err; }); });
        }
      }
    }

    // DOM ready, taken from https://github.com/jquery/jquery/blob/master/src/core/ready.js#L63
    if (document.readyState === 'complete') {
      setTimeout(ready);
    }
    else if (document.addEventListener) {
      document.addEventListener('DOMContentLoaded', completed, false);
      window.addEventListener('load', completed, false);
    }
  }
})();
  // -- exporting --

  if (typeof exports === 'object')
    module.exports = Loader;

  __global.Reflect = __global.Reflect || {};
  __global.Reflect.Loader = __global.Reflect.Loader || Loader;
  __global.Reflect.global = __global.Reflect.global || __global;
  __global.LoaderPolyfill = Loader;

  if (!System) {
    System = new SystemLoader();
    System.constructor = SystemLoader;
  }

  if (typeof exports === 'object')
    module.exports = System;

  __global.System = System;

})(typeof self != 'undefined' ? self : global);