1 files changed, 70 insertions, 0 deletions
diff --git a/node_modules/rxjs/src/internal/operators/observeOn.ts b/node_modules/rxjs/src/internal/operators/observeOn.ts
new file mode 100644
index 0000000..bd37111
--- /dev/null
+++ b/node_modules/rxjs/src/internal/operators/observeOn.ts
@@ -0,0 +1,70 @@
+/** @prettier */
+import { MonoTypeOperatorFunction, SchedulerLike } from '../types';
+import { executeSchedule } from '../util/executeSchedule';
+import { operate } from '../util/lift';
+import { createOperatorSubscriber } from './OperatorSubscriber';
+
+/**
+ * Re-emits all notifications from source Observable with specified scheduler.
+ *
+ * <span class="informal">Ensure a specific scheduler is used, from outside of an Observable.</span>
+ *
+ * `observeOn` is an operator that accepts a scheduler as a first parameter, which will be used to reschedule
+ * notifications emitted by the source Observable. It might be useful, if you do not have control over
+ * internal scheduler of a given Observable, but want to control when its values are emitted nevertheless.
+ *
+ * Returned Observable emits the same notifications (nexted values, complete and error events) as the source Observable,
+ * but rescheduled with provided scheduler. Note that this doesn't mean that source Observables internal
+ * scheduler will be replaced in any way. Original scheduler still will be used, but when the source Observable emits
+ * notification, it will be immediately scheduled again - this time with scheduler passed to `observeOn`.
+ * An anti-pattern would be calling `observeOn` on Observable that emits lots of values synchronously, to split
+ * that emissions into asynchronous chunks. For this to happen, scheduler would have to be passed into the source
+ * Observable directly (usually into the operator that creates it). `observeOn` simply delays notifications a
+ * little bit more, to ensure that they are emitted at expected moments.
+ *
+ * As a matter of fact, `observeOn` accepts second parameter, which specifies in milliseconds with what delay notifications
+ * will be emitted. The main difference between {@link delay} operator and `observeOn` is that `observeOn`
+ * will delay all notifications - including error notifications - while `delay` will pass through error
+ * from source Observable immediately when it is emitted. In general it is highly recommended to use `delay` operator
+ * for any kind of delaying of values in the stream, while using `observeOn` to specify which scheduler should be used
+ * for notification emissions in general.
+ *
+ * ## Example
+ *
+ * Ensure values in subscribe are called just before browser repaint
+ *
+ * ```ts
+ * import { interval, observeOn, animationFrameScheduler } from 'rxjs';
+ *
+ * const someDiv = document.createElement('div');
+ * someDiv.style.cssText = 'width: 200px;background: #09c';
+ * document.body.appendChild(someDiv);
+ * const intervals = interval(10);      // Intervals are scheduled
+ *                                      // with async scheduler by default...
+ * intervals.pipe(
+ *   observeOn(animationFrameScheduler) // ...but we will observe on animationFrame
+ * )                                    // scheduler to ensure smooth animation.
+ * .subscribe(val => {
+ *   someDiv.style.height = val + 'px';
+ * });
+ * ```
+ *
+ * @see {@link delay}
+ *
+ * @param scheduler Scheduler that will be used to reschedule notifications from source Observable.
+ * @param delay Number of milliseconds that states with what delay every notification should be rescheduled.
+ * @return A function that returns an Observable that emits the same
+ * notifications as the source Observable, but with provided scheduler.
+ */
+export function observeOn<T>(scheduler: SchedulerLike, delay = 0): MonoTypeOperatorFunction<T> {
+  return operate((source, subscriber) => {
+    source.subscribe(
+      createOperatorSubscriber(
+        subscriber,
+        (value) => executeSchedule(subscriber, scheduler, () => subscriber.next(value), delay),
+        () => executeSchedule(subscriber, scheduler, () => subscriber.complete(), delay),
+        (err) => executeSchedule(subscriber, scheduler, () => subscriber.error(err), delay)
+      )
+    );
+  });
+}