Initial project import

node_modules/rxjs/src/internal/operators/timestamp.ts

@@ -0,0 +1,39 @@
+import { OperatorFunction, TimestampProvider, Timestamp } from '../types';
+import { dateTimestampProvider } from '../scheduler/dateTimestampProvider';
+import { map } from './map';
+
+/**
+ * Attaches a timestamp to each item emitted by an observable indicating when it was emitted
+ *
+ * The `timestamp` operator maps the *source* observable stream to an object of type
+ * `{value: T, timestamp: R}`. The properties are generically typed. The `value` property contains the value
+ * and type of the *source* observable. The `timestamp` is generated by the schedulers `now` function. By
+ * default, it uses the `asyncScheduler` which simply returns `Date.now()` (milliseconds since 1970/01/01
+ * 00:00:00:000) and therefore is of type `number`.
+ *
+ * ![](timestamp.png)
+ *
+ * ## Example
+ *
+ * In this example there is a timestamp attached to the document's click events
+ *
+ * ```ts
+ * import { fromEvent, timestamp } from 'rxjs';
+ *
+ * const clickWithTimestamp = fromEvent(document, 'click').pipe(
+ *   timestamp()
+ * );
+ *
+ * // Emits data of type { value: PointerEvent, timestamp: number }
+ * clickWithTimestamp.subscribe(data => {
+ *   console.log(data);
+ * });
+ * ```
+ *
+ * @param timestampProvider An object with a `now()` method used to get the current timestamp.
+ * @return A function that returns an Observable that attaches a timestamp to
+ * each item emitted by the source Observable indicating when it was emitted.
+ */
+export function timestamp<T>(timestampProvider: TimestampProvider = dateTimestampProvider): OperatorFunction<T, Timestamp<T>> {
+  return map((value: T) => ({ value, timestamp: timestampProvider.now() }));
+}