[changed] enums to be string consts

Summary:
It just feels more JavaScripty.  FWIW, I think enums are a feature the TS team now regrets - it goes against their general ethos of "pure JS + types".

Closes #155

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

Reviewed By: O2 Material Motion, #material_motion, featherless

Tags: #material_motion

Differential Revision: http://codereview.cc/D3126

packages/core/src/GestureRecognitionState.ts

@@ -14,14 +14,14 @@
  *  under the License.
  */
 
-export enum GestureRecognitionState {
-  POSSIBLE,
-  BEGAN,
-  CHANGED,
-  ENDED,
-  CANCELLED,
-  FAILED,
-  RECOGNIZED = ENDED,
+export const GestureRecognitionState = {
+  POSSIBLE: 'possible',
+  BEGAN: 'began',
+  CHANGED: 'changed',
+  ENDED: 'ended',
+  RECOGNIZED: 'ended',
+  CANCELLED: 'cancelled',
+  FAILED: 'failed',
 };
 
 export default GestureRecognitionState;

packages/core/src/State.ts

@@ -14,8 +14,8 @@
  *  under the License.
  */
 
-export enum State {
-  AT_REST = 0,
-  ACTIVE = 1,
-}
+export const State = {
+  AT_REST: 'at_rest',
+  ACTIVE: 'active',
+};
 export default State;

packages/core/src/ThresholdSide.ts

@@ -14,8 +14,6 @@
  *  under the License.
  */
 
-// Using const instead of enum because `'above'` is more meaningful in a log/to
-// JS developers than `0`.
 export const ThresholdSide = {
   ABOVE: 'above',
   WITHIN: 'within',

packages/demos-react/src/QuickiePointerEventTest.tsx

@@ -116,7 +116,7 @@ export class QuickiePointerEventTest extends React.Component {
               State
             </td>
             <td>
-              { GestureRecognitionState[state] }
+              { state }
             </td>
           </tr>
           <tr>