polymer.js

/*
 * Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 * The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 * The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 * Code distributed by Google as part of the polymer project is also
 * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */

(function(scope) {

  // imports

  var extend = scope.extend;
  var api = scope.api;

  // imperative implementation: Polymer()

  // specify an 'own' prototype for tag `name`
  function element(name, prototype) {
    if (typeof name !== 'string') {
      var script = prototype || document._currentScript;
      prototype = name;
      name = script && script.parentNode && script.parentNode.getAttribute ?
          script.parentNode.getAttribute('name') : '';
      if (!name) {
        throw 'Element name could not be inferred.';
      }
    }
    if (getRegisteredPrototype(name)) {
      throw 'Already registered (Polymer) prototype for element ' + name;
    }
    // cache the prototype
    registerPrototype(name, prototype);
    // notify the registrar waiting for 'name', if any
    notifyPrototype(name);
  }

  // async prototype source

  function waitingForPrototype(name, client) {
    waitPrototype[name] = client;
  }

  var waitPrototype = {};

  function notifyPrototype(name) {
    if (waitPrototype[name]) {
      waitPrototype[name].registerWhenReady();
      delete waitPrototype[name];
    }
  }

  // utility and bookkeeping

  // maps tag names to prototypes, as registered with
  // Polymer. Prototypes associated with a tag name
  // using document.registerElement are available from
  // HTMLElement.getPrototypeForTag().
  // If an element was fully registered by Polymer, then
  // Polymer.getRegisteredPrototype(name) === 
  //   HTMLElement.getPrototypeForTag(name)

  var prototypesByName = {};

  function registerPrototype(name, prototype) {
    return prototypesByName[name] = prototype || {};
  }

  function getRegisteredPrototype(name) {
    return prototypesByName[name];
  }

  function instanceOfType(element, type) {
    if (typeof type !== 'string') {
      return false;
    }
    var proto = HTMLElement.getPrototypeForTag(type);
    var ctor = proto && proto.constructor;
    if (!ctor) {
      return false;
    }
    if (CustomElements.instanceof) {
      return CustomElements.instanceof(element, ctor);
    }
    return element instanceof ctor;
  }

  // exports

  scope.getRegisteredPrototype = getRegisteredPrototype;
  scope.waitingForPrototype = waitingForPrototype;
  scope.instanceOfType = instanceOfType;

  // namespace shenanigans so we can expose our scope on the registration 
  // function

  // make window.Polymer reference `element()`

  window.Polymer = element;

  // TODO(sjmiles): find a way to do this that is less terrible
  // copy window.Polymer properties onto `element()`

  extend(Polymer, scope);

  // Under the HTMLImports polyfill, scripts in the main document
  // do not block on imports; we want to allow calls to Polymer in the main
  // document. WebComponents collects those calls until we can process them, which
  // we do here.

  if (WebComponents.consumeDeclarations) {
    WebComponents.consumeDeclarations(function(declarations) {;
      if (declarations) {
        for (var i=0, l=declarations.length, d; (i<l) && (d=declarations[i]); i++) {
          element.apply(null, d);
        }
      }
    });
  }

})(Polymer);