feat(sample): notifier now supports any ObservableInput (#7104)

* feat(sample): add ObservableInput support in notifier

* test(sample): added tests for sample's ObservableInput notifier

* chore(sample): cleanup unused declaration

* Delete index.d.ts

* Delete index.d.ts

Co-authored-by: Ben Lesh <ben@benlesh.com>

spec-dtslint/operators/sample-spec.ts

@@ -1,11 +1,77 @@
 import { of } from 'rxjs';
 import { sample } from 'rxjs/operators';
+import { asInteropObservable } from '../../spec/helpers/interop-helper';
 
 it('should enforce parameter', () => {
-  const a = of(1, 2, 3).pipe(sample()); // $ExpectError
+  of(1, 2, 3).pipe(sample()); // $ExpectError
 });
 
 it('should accept observable as notifier parameter', () => {
-  const a = of(1, 2, 3).pipe(sample(of(4))); // $ExpectType Observable<number>
-  const b = of(1, 2, 3).pipe(sample(of('a'))); // $ExpectType Observable<number>
+  of(1, 2, 3).pipe(sample(of(4))); // $ExpectType Observable<number>
+  of(1, 2, 3).pipe(sample(of('a'))); // $ExpectType Observable<number>
+});
+
+it('should accept interop observable notifier', () => {
+  of(1, 2, 3).pipe(sample(asInteropObservable(of(true)))); // $ExpectType Observable<number>
+});
+
+it('should accept promise notifier', () => {
+  of(1, 2, 3).pipe(sample(Promise.resolve(true))); // $ExpectType Observable<number>
+});
+
+it('should async iterable notifier', () => {
+  const asyncRange = {
+    from: 1,
+    to: 2,
+    [Symbol.asyncIterator]() {
+      return {
+        current: this.from,
+        last: this.to,
+        async next() {
+          await Promise.resolve();
+          const done = (this.current > this.last);
+          return {
+            done,
+            value: done ? this.current++ : undefined
+          };
+        }
+      };
+    }
+  };
+  of(1, 2, 3).pipe(sample(asyncRange)); // $ExpectType Observable<number>
+});
+
+it('should accept iterable notifier', () => {
+  const syncRange = {
+    from: 1,
+    to: 2,
+    [Symbol.iterator]() {
+      return {
+        current: this.from,
+        last: this.to,
+        next() {
+          const done = (this.current > this.last);
+          return {
+            done,
+            value: done ? this.current++ : undefined
+          };
+        }
+      };
+    }
+  };
+  of(1, 2, 3).pipe(sample(syncRange)); // $ExpectType Observable<number>
+});
+
+it('should accept readable stream notifier', () => {
+  const readableStream = new ReadableStream<string>({
+    pull(controller) {
+      controller.enqueue('x');
+      controller.close();
+    },
+  });
+  of(1, 2, 3).pipe(sample(readableStream)); // $ExpectType Observable<number>
+});
+
+it('should enforce types of the notifier', () => {
+  of(1, 2, 3).pipe(sample(8)); // $ExpectError
 });

src/internal/operators/sample.ts

@@ -1,5 +1,5 @@
-import { Observable } from '../Observable';
-import { MonoTypeOperatorFunction } from '../types';
+import { innerFrom } from '../observable/innerFrom';
+import { MonoTypeOperatorFunction, ObservableInput } from '../types';
 import { operate } from '../util/lift';
 import { noop } from '../util/noop';
 import { createOperatorSubscriber } from './OperatorSubscriber';
@@ -9,11 +9,11 @@ import { createOperatorSubscriber } from './OperatorSubscriber';
  * another Observable, the `notifier`, emits.
  *
  * <span class="informal">It's like {@link sampleTime}, but samples whenever
- * the `notifier` Observable emits something.</span>
+ * the `notifier` `ObservableInput` emits something.</span>
  *
  * ![](sample.png)
  *
- * Whenever the `notifier` Observable emits a value, `sample`
+ * Whenever the `notifier` `ObservableInput` emits a value, `sample`
  * looks at the source Observable and emits whichever value it has most recently
  * emitted since the previous sampling, unless the source has not emitted
  * anything since the previous sampling. The `notifier` is subscribed to as soon
@@ -38,13 +38,13 @@ import { createOperatorSubscriber } from './OperatorSubscriber';
  * @see {@link sampleTime}
  * @see {@link throttle}
  *
- * @param notifier The Observable to use for sampling the
+ * @param notifier The `ObservableInput` to use for sampling the
  * source Observable.
  * @return A function that returns an Observable that emits the results of
  * sampling the values emitted by the source Observable whenever the notifier
  * Observable emits value or completes.
  */
-export function sample<T>(notifier: Observable<any>): MonoTypeOperatorFunction<T> {
+export function sample<T>(notifier: ObservableInput<any>): MonoTypeOperatorFunction<T> {
   return operate((source, subscriber) => {
     let hasValue = false;
     let lastValue: T | null = null;
@@ -54,7 +54,7 @@ export function sample<T>(notifier: Observable<any>): MonoTypeOperatorFunction<T
         lastValue = value;
       })
     );
-    notifier.subscribe(
+    innerFrom(notifier).subscribe(
       createOperatorSubscriber(
         subscriber,
         () => {