[refactored] threshold to have shorthand signature

Summary: Part of #230 Reviewers: O2 Material Motion, O3 Material JavaScript platform reviewers, #material_motion, vietanh Reviewed By: #material_motion, vietanh Tags: #material_motion Differential Revision: http://codereview.cc/D3428
material-motion · Oct 11, 2017 · 6aaa6cd · 6aaa6cd
1 parent d3e7b3e
commit 6aaa6cd
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Showing 3 changed files with 32 additions and 10 deletions.
diff --git a/packages/core/src/interactions/Swipeable.ts b/packages/core/src/interactions/Swipeable.ts
@@ -160,7 +160,7 @@ export class Swipeable {
       })
     });
 
-    this.direction$ = draggedX$.threshold({ limit$: 0 }).isAnyOf([ ThresholdRegion.ABOVE ]).rewrite({
+    this.direction$ = draggedX$.threshold(0).isAnyOf([ ThresholdRegion.ABOVE ]).rewrite({
       mapping: {
         true: Direction.RIGHT,
         false: Direction.LEFT,
@@ -174,7 +174,7 @@ export class Swipeable {
     // `resistanceProgress`. Thus, we independently calculate the threshold
     // here.
 
-    this.isThresholdMet$ = draggedX$.distanceFrom(0).threshold({ limit$: Swipeable.VISUAL_THRESHOLD }).isAnyOf([
+    this.isThresholdMet$ = draggedX$.distanceFrom(0).threshold(Swipeable.VISUAL_THRESHOLD).isAnyOf([
       ThresholdRegion.ABOVE,
       ThresholdRegion.WITHIN,
     ]);

diff --git a/packages/core/src/operators/__tests__/threshold.test.ts b/packages/core/src/operators/__tests__/threshold.test.ts
@@ -117,5 +117,15 @@ describe('motionObservable.threshold',
         expect(listener).to.have.been.calledTwice.and.to.have.been.calledWith(ThresholdRegion.BELOW);
       }
     );
+
+    it('should have a shorthand signature',
+      () => {
+        subject.threshold(7).subscribe(listener);
+
+        subject.next(3);
+
+        expect(listener).to.have.been.calledWith(ThresholdRegion.BELOW);
+      }
+    );
   }
 );
diff --git a/packages/core/src/operators/threshold.ts b/packages/core/src/operators/threshold.ts
@@ -14,6 +14,10 @@
  *  under the License.
  */
 
+import {
+  ThresholdRegion,
+} from '../enums';
+
 import {
   Constructor,
   MaybeReactive,
@@ -23,24 +27,32 @@ import {
 } from '../types';
 
 import {
-  ThresholdRegion,
-} from '../enums';
+  isDefined,
+} from '../typeGuards';
 
 import {
   _ReactiveMapOptions,
 } from './foundation/_reactiveMap';
 
-export type ThresholdArgs = _ReactiveMapOptions & MaybeReactive<{
-  limit$: number,
-}>;
+export type ThresholdLimit = number | Observable<number>;
+export type ThresholdArgs = _ReactiveMapOptions & {
+  limit$: ThresholdLimit,
+};
 
 export interface MotionThresholdable {
+  threshold(limit$: ThresholdLimit): ObservableWithMotionOperators<ThresholdRegion>;
   threshold(kwargs: ThresholdArgs): ObservableWithMotionOperators<ThresholdRegion>;
 }
 
 export function withThreshold<T, S extends Constructor<MotionReactiveMappable<T>>>(superclass: S): S & Constructor<MotionThresholdable> {
   return class extends superclass implements MotionThresholdable {
-    threshold({ limit$, ...reactiveMapOptions }: ThresholdArgs): ObservableWithMotionOperators<ThresholdRegion> {
+    threshold(limit$: ThresholdLimit): ObservableWithMotionOperators<ThresholdRegion>;
+    threshold(kwargs: ThresholdArgs): ObservableWithMotionOperators<ThresholdRegion>;
+    threshold({ limit$, ...reactiveMapOptions }: any): ObservableWithMotionOperators<ThresholdRegion> {
+      if (!isDefined(limit$)) {
+        limit$ = arguments[0];
+      }
+
       return (this as any as MotionReactiveMappable<number>)._reactiveMap({
         transform: ({ upstream, limit }) => {
           if (upstream < limit) {
@@ -53,9 +65,9 @@ export function withThreshold<T, S extends Constructor<MotionReactiveMappable<T>
           }
         },
         inputs: {
-          limit: limit$,
+          limit: limit$ as ThresholdLimit,
         },
-        ...reactiveMapOptions,
+        ...reactiveMapOptions as _ReactiveMapOptions,
       });
     }
   };