[added] MotionSubject

Summary: Related: #194

Reviewers: O2 Material Motion, O3 Material JavaScript platform reviewers, #material_motion, featherless

Reviewed By: O2 Material Motion, #material_motion, featherless

Subscribers: featherless

Tags: #material_motion

Differential Revision: http://codereview.cc/D3131

packages/core/src/observables/MotionSubject.ts

@@ -0,0 +1,41 @@
+/** @license
+ *  Copyright 2016 - present The Material Motion Authors. All Rights Reserved.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ *  use this file except in compliance with the License. You may obtain a copy
+ *  of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ *  License for the specific language governing permissions and limitations
+ *  under the License.
+ */
+
+import {
+  MotionObservable,
+} from '../observables';
+
+// ObservableWithMotionOperators isn't referenced in this file, but TypeScript
+// gets mad if you remove it. (MotionSubject is using MotionDebounceable from an
+// external module)
+import {
+  ObservableWithMotionOperators,
+  withMotionOperators,
+} from '../operators';
+
+import {
+  Operable,
+} from '../types';
+
+import {
+  IndefiniteSubject,
+} from './IndefiniteSubject';
+
+export class OperableSubject<T> extends IndefiniteSubject<T> implements Operable<T> {
+  _observableConstructor = MotionObservable;
+}
+export const MotionSubject = withMotionOperators(OperableSubject);
+export default MotionSubject;

packages/core/src/observables/__tests__/motionSubject.test.ts

@@ -0,0 +1,64 @@
+/** @license
+ *  Copyright 2016 - present The Material Motion Authors. All Rights Reserved.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ *  use this file except in compliance with the License. You may obtain a copy
+ *  of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ *  License for the specific language governing permissions and limitations
+ *  under the License.
+ */
+
+import { expect } from 'chai';
+
+import {
+  beforeEach,
+  describe,
+  it,
+} from 'mocha-sugar-free';
+
+import {
+  spy,
+} from 'sinon';
+
+import MotionSubject from '../MotionSubject';
+
+declare function require(name: string);
+
+// chai really doesn't like being imported as an ES2015 module; will be fixed in v4
+require('chai').use(
+  require('sinon-chai')
+);
+
+describe('motionSubject',
+  () => {
+    let subject;
+    let listener;
+
+    beforeEach(
+      () => {
+        subject = new MotionSubject();
+
+        listener = spy();
+      }
+    );
+
+    it(`should be a subject with operators`,
+      () => {
+        subject.pluck('a').subscribe(listener);
+
+        subject.next({ 'a': 1 });
+
+        expect(listener).to.have.been.calledOnce.and.to.have.been.calledWith(1);
+      }
+    );
+
+    // It would be more thorough to re-run the IndefiniteSubject and operator
+    // test suites here, but I'm not sure it adds value/
+  }
+);

packages/core/src/observables/index.ts

@@ -20,4 +20,7 @@ export { default as IndefiniteSubject } from './IndefiniteSubject';
 export * from './MotionObservable';
 export { default as MotionObservable } from './MotionObservable';
 
+export * from './MotionSubject';
+export { default as MotionSubject } from './MotionSubject';
+
 export default undefined;