emberjs · mmun · Jan 3, 2015 · Dec 31, 2014 · stefanpenner · Jan 2, 2015
diff --git a/features.json b/features.json
@@ -7,6 +7,7 @@
     "ember-htmlbars": true,
     "ember-htmlbars-block-params": true,
     "ember-htmlbars-component-generation": null,
+    "ember-htmlbars-component-helper": null,
     "ember-htmlbars-inline-if-helper": true,
     "ember-htmlbars-attribute-syntax": null,
     "ember-routing-transitioning-classes": true

diff --git a/packages/ember-htmlbars/lib/helpers/component.js b/packages/ember-htmlbars/lib/helpers/component.js
@@ -0,0 +1,92 @@
+/**
+@module ember
+@submodule ember-htmlbars
+*/
+import Ember from "ember-metal/core"; // Ember.warn, Ember.assert
+import { isStream, read } from "ember-metal/streams/utils";
+import { readComponentFactory } from "ember-views/streams/utils";
+import EmberError from "ember-metal/error";
+import BoundComponentView from "ember-views/views/bound_component_view";
+import mergeViewBindings from "ember-htmlbars/system/merge-view-bindings";
+import appendTemplatedView from "ember-htmlbars/system/append-templated-view";
+
+/**
+  The `{{component}}` helper lets you add instances of `Ember.Component` to a
+  template. See [Ember.Component](/api/classes/Ember.Component.html) for
+  additional information on how a `Component` functions.
+
+  `{{component}}`'s primary use is for cases where you want to dynamically
+  change which type of component is rendered as the state of your application
+  changes.
+
+  The provided block will be applied as the template for the component.
+
+  Given an empty `<body>` the following template:
+
+  ```handlebars
+  {{! application.hbs }}
+  {{component infographicComponentName}}
+  ```
+
+  And the following application code
+
+  ```javascript
+  App = Ember.Application.create();
+  App.ApplicationController = Ember.Controller.extend({
+    infographicComponentName: function(){
+      if (this.get('isMarketOpen')) {
+        return "live-updating-chart";
+      } else {
+        return "market-close-summary";
+      }
+    }.property('isMarketOpen')
+  });
+  ```
+
+  The `live-updating-chart` component will be appended when `isMarketOpen` is
+  `true`, and the `market-close-summary` component will be appended when
+  `isMarketOpen` is `false`. If the value changes while the app is running,
+  the component will be automatically swapped out accordingly.
+
+  Note: You should not use this helper when you are consistently rendering the same
+  component. In that case, use standard component syntax, for example:
+
+  ```handlebars
+  {{! application.hbs }}
+  {{live-updating-chart}}
+  ```
+
+  @method component
+  @for Ember.Handlebars.helpers
+*/
+export function componentHelper(params, hash, options, env) {
+  Ember.assert(
+    "The `component` helper expects exactly one argument, plus name/property values.",
+    params.length === 1
+  );
+
+  var componentNameParam = params[0];
+  var container = this.container || read(this._keywords.view).container;
+
+  var props = {
+    helperName: options.helperName || 'component'
+  };
+  if (options.template) {
+    props.template = options.template;
+  }
+
+  var viewClass;
+  if (isStream(componentNameParam)) {
+    viewClass = BoundComponentView;
+    props = { _boundComponentOptions: Ember.merge(hash, props) };
+    props._boundComponentOptions.componentNameStream = componentNameParam;
+  } else {
+    viewClass = readComponentFactory(componentNameParam, container);
+    if (!viewClass) {
+      throw new EmberError('HTMLBars error: Could not find component named "' + componentNameParam + '".');
+    }
+    mergeViewBindings(this, props, hash);
+  }
+
+  appendTemplatedView(this, options.morph, viewClass, props);
+}
diff --git a/packages/ember-htmlbars/lib/main.js b/packages/ember-htmlbars/lib/main.js
@@ -27,6 +27,7 @@ import {
   default as helpers
 } from "ember-htmlbars/helpers";
 import { viewHelper } from "ember-htmlbars/helpers/view";
+import { componentHelper } from "ember-htmlbars/helpers/component";
 import { yieldHelper } from "ember-htmlbars/helpers/yield";
 import { withHelper } from "ember-htmlbars/helpers/with";
 import { logHelper } from "ember-htmlbars/helpers/log";
@@ -59,6 +60,9 @@ import "ember-htmlbars/system/bootstrap";
 import "ember-htmlbars/compat";
 
 registerHelper('view', viewHelper);
+if (Ember.FEATURES.isEnabled('ember-htmlbars-component-helper')) {
+  registerHelper('component', componentHelper);
+}
 registerHelper('yield', yieldHelper);
 registerHelper('with', withHelper);
 registerHelper('if', ifHelper);

diff --git a/packages/ember-htmlbars/tests/helpers/component_test.js b/packages/ember-htmlbars/tests/helpers/component_test.js
@@ -0,0 +1,167 @@
+import ComponentLookup from "ember-views/component_lookup";
+import Registry from "container/registry";
+import EmberView from "ember-views/views/view";
+import compile from "ember-template-compiler/system/compile";
+import { runAppend, runDestroy } from "ember-runtime/tests/utils";
+
+var set = Ember.set;
+var get = Ember.get;
+var view, registry, container;
+
+if (Ember.FEATURES.isEnabled('ember-htmlbars-component-helper')) {
+  QUnit.module("ember-htmlbars: {{#component}} helper", {
+    setup: function() {
+      registry = new Registry();
+      container = registry.container();
+
+      registry.optionsForType('template', { instantiate: false });
+      registry.register('component-lookup:main', ComponentLookup);
+    },
+
+    teardown: function() {
+      runDestroy(view);
+      runDestroy(container);
+      registry = container = view = null;
+    }
+  });
+
+  test("component helper with unquoted string is bound", function() {
+    registry.register('template:components/foo-bar', compile('yippie! {{location}} {{yield}}'));
+    registry.register('template:components/baz-qux', compile('yummy {{location}} {{yield}}'));
+
+    view = EmberView.create({
+      container: container,
+      dynamicComponent: 'foo-bar',
+      location: 'Caracas',
+      template: compile('{{#component view.dynamicComponent location=view.location}}arepas!{{/component}}')
+    });
+
+    runAppend(view);
+    equal(view.$().text(), 'yippie! Caracas arepas!', 'component was looked up and rendered');
+
+    Ember.run(function() {
+      set(view, "dynamicComponent", 'baz-qux');
+      set(view, "location", 'Loisaida');
+    });
+    equal(view.$().text(), 'yummy Loisaida arepas!', 'component was updated and re-rendered');
+  });
+
+  test("component helper with actions", function() {
+    registry.register('template:components/foo-bar', compile('yippie! {{yield}}'));
+    registry.register('component:foo-bar', Ember.Component.extend({
+      classNames: 'foo-bar',
+      didInsertElement: function() {
+        // trigger action on click in absence of app's EventDispatcher
+        var self = this;
+        this.$().on('click', function() {
+          self.sendAction('fooBarred');
+        });
+      },
+      willDestroyElement: function() {
+        this.$().off('click');
+      }
+    }));
+
+    var actionTriggered = 0;
+    var controller = Ember.Controller.extend({
+      dynamicComponent: 'foo-bar',
+      actions: {
+        mappedAction: function() {
+          actionTriggered++;
+        }
+      }
+    }).create();
+    view = EmberView.create({
+      container: container,
+      controller: controller,
+      template: compile('{{#component dynamicComponent fooBarred="mappedAction"}}arepas!{{/component}}')
+    });
+
+    runAppend(view);
+    Ember.run(function() {
+      view.$('.foo-bar').trigger('click');
+    });
+    equal(actionTriggered, 1, 'action was triggered');
+  });
+
+  test('component helper maintains expected logical parentView', function() {
+    registry.register('template:components/foo-bar', compile('yippie! {{yield}}'));
+    var componentInstance;
+    registry.register('component:foo-bar', Ember.Component.extend({
+      didInsertElement: function() {
+        componentInstance = this;
+      }
+    }));
+
+    view = EmberView.create({
+      container: container,
+      dynamicComponent: 'foo-bar',
+      template: compile('{{#component view.dynamicComponent}}arepas!{{/component}}')
+    });
+
+    runAppend(view);
+    equal(get(componentInstance, 'parentView'), view, 'component\'s parentView is the view invoking the helper');
+  });
+
+  test("nested component helpers", function() {
+    registry.register('template:components/foo-bar', compile('yippie! {{location}} {{yield}}'));
+    registry.register('template:components/baz-qux', compile('yummy {{location}} {{yield}}'));
+    registry.register('template:components/corge-grault', compile('delicious {{location}} {{yield}}'));
+
+    view = EmberView.create({
+      container: container,
+      dynamicComponent1: 'foo-bar',
+      dynamicComponent2: 'baz-qux',
+      location: 'Caracas',
+      template: compile('{{#component view.dynamicComponent1 location=view.location}}{{#component view.dynamicComponent2 location=view.location}}arepas!{{/component}}{{/component}}')
+    });
+
+    runAppend(view);
+    equal(view.$().text(), 'yippie! Caracas yummy Caracas arepas!', 'components were looked up and rendered');
+
+    Ember.run(function() {
+      set(view, "dynamicComponent1", 'corge-grault');
+      set(view, "location", 'Loisaida');
+    });
+    equal(view.$().text(), 'delicious Loisaida yummy Loisaida arepas!', 'components were updated and re-rendered');
+  });
+
+  test("component helper can be used with a quoted string (though you probably would not do this)", function() {
+    registry.register('template:components/foo-bar', compile('yippie! {{location}} {{yield}}'));
+
+    view = EmberView.create({
+      container: container,
+      location: 'Caracas',
+      template: compile('{{#component "foo-bar" location=view.location}}arepas!{{/component}}')
+    });
+
+    runAppend(view);
+
+    equal(view.$().text(), 'yippie! Caracas arepas!', 'component was looked up and rendered');
+  });
+
+  test("component with unquoted param resolving to non-existent component", function() {
+    view = EmberView.create({
+      container: container,
+      dynamicComponent: 'does-not-exist',
+      location: 'Caracas',
+      template: compile('{{#component view.dynamicComponent location=view.location}}arepas!{{/component}}')
+    });
+
+    throws(function() {
+      runAppend(view);
+    }, /HTMLBars error: Could not find component named "does-not-exist"./);
+  });
+
+  test("component with quoted param for non-existent component", function() {
+    view = EmberView.create({
+      container: container,
+      location: 'Caracas',
+      template: compile('{{#component "does-not-exist" location=view.location}}arepas!{{/component}}')
+    });
+
+    throws(function() {
+      runAppend(view);
+    }, /HTMLBars error: Could not find component named "does-not-exist"./);
+  });
+}
diff --git a/packages/ember-views/lib/streams/utils.js b/packages/ember-views/lib/streams/utils.js
@@ -27,6 +27,15 @@ export function readViewFactory(object, container) {
   return viewClass;
 }
 
+export function readComponentFactory(nameOrStream, container) {
+  var name = read(nameOrStream);
+  var componentLookup = container.lookup('component-lookup:main');
+  Ember.assert("Could not find 'component-lookup:main' on the provided container," +
+               " which is necessary for performing component lookups", componentLookup);
+
+  return componentLookup.lookupFactory(name, container);
+}
+
 export function readUnwrappedModel(object) {
   if (isStream(object)) {
     var result = object.value();

diff --git a/packages/ember-views/lib/views/bound_component_view.js b/packages/ember-views/lib/views/bound_component_view.js
@@ -0,0 +1,50 @@
+/**
+@module ember
+@submodule ember-views
+*/
+
+import { _Metamorph } from "ember-views/views/metamorph_view";
+import { read, chain, subscribe, unsubscribe } from "ember-metal/streams/utils";
+import { readComponentFactory } from "ember-views/streams/utils";
+import mergeViewBindings from "ember-htmlbars/system/merge-view-bindings";
+import EmberError from "ember-metal/error";
+
+export default Ember.ContainerView.extend(_Metamorph, {
+  init: function() {
+    this._super();
+    var componentNameStream = this._boundComponentOptions.componentNameStream;
+    var container = this.container;
+    this.componentClassStream = chain(componentNameStream, function() {
+      return readComponentFactory(componentNameStream, container);
+    });
+
+    subscribe(this.componentClassStream, this._updateBoundChildComponent, this);
+    this._updateBoundChildComponent();
+  },
+  willDestroy: function() {
+    unsubscribe(this.componentClassStream, this._updateBoundChildComponent, this);
+    this._super();
+  },
+  _updateBoundChildComponent: function() {
+    this.replace(0, 1, [this._createNewComponent()]);
+  },
+  _createNewComponent: function() {
+    var componentClass = read(this.componentClassStream);
+    if (!componentClass) {
+      throw new EmberError('HTMLBars error: Could not find component named "' + read(this._boundComponentOptions.componentNameStream) + '".');
+    }
+    var hash    = this._boundComponentOptions;
+    var ignore  = ["_boundComponentOptions", "componentClassStream"];
+    var hashForComponent = {};
+
+    var prop;
+    for (prop in hash) {
+      if (ignore.indexOf(prop) !== -1) { continue; }
+      hashForComponent[prop] = hash[prop];
+    }
+
+    var props   = {};
+    mergeViewBindings(this, props, hashForComponent);
+    return this.createChildView(componentClass, props);
+  }
+});