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+import { OperatorFunction, MonoTypeOperatorFunction, TruthyTypesOf } from '../types';
+import { operate } from '../util/lift';
+import { createOperatorSubscriber } from './OperatorSubscriber';
+
+export function takeWhile<T>(predicate: BooleanConstructor, inclusive: true): MonoTypeOperatorFunction<T>;
+export function takeWhile<T>(predicate: BooleanConstructor, inclusive: false): OperatorFunction<T, TruthyTypesOf<T>>;
+export function takeWhile<T>(predicate: BooleanConstructor): OperatorFunction<T, TruthyTypesOf<T>>;
+export function takeWhile<T, S extends T>(predicate: (value: T, index: number) => value is S): OperatorFunction<T, S>;
+export function takeWhile<T, S extends T>(predicate: (value: T, index: number) => value is S, inclusive: false): OperatorFunction<T, S>;
+export function takeWhile<T>(predicate: (value: T, index: number) => boolean, inclusive?: boolean): MonoTypeOperatorFunction<T>;
+
+/**
+ * Emits values emitted by the source Observable so long as each value satisfies
+ * the given `predicate`, and then completes as soon as this `predicate` is not
+ * satisfied.
+ *
+ * <span class="informal">Takes values from the source only while they pass the
+ * condition given. When the first value does not satisfy, it completes.</span>
+ *
+ * ![](takeWhile.png)
+ *
+ * `takeWhile` subscribes and begins mirroring the source Observable. Each value
+ * emitted on the source is given to the `predicate` function which returns a
+ * boolean, representing a condition to be satisfied by the source values. The
+ * output Observable emits the source values until such time as the `predicate`
+ * returns false, at which point `takeWhile` stops mirroring the source
+ * Observable and completes the output Observable.
+ *
+ * ## Example
+ *
+ * Emit click events only while the clientX property is greater than 200
+ *
+ * ```ts
+ * import { fromEvent, takeWhile } from 'rxjs';
+ *
+ * const clicks = fromEvent<PointerEvent>(document, 'click');
+ * const result = clicks.pipe(takeWhile(ev => ev.clientX > 200));
+ * result.subscribe(x => console.log(x));
+ * ```
+ *
+ * @see {@link take}
+ * @see {@link takeLast}
+ * @see {@link takeUntil}
+ * @see {@link skip}
+ *
+ * @param predicate A function that evaluates a value emitted by the source
+ * Observable and returns a boolean. Also takes the (zero-based) index as the
+ * second argument.
+ * @param inclusive When set to `true` the value that caused `predicate` to
+ * return `false` will also be emitted.
+ * @return A function that returns an Observable that emits values from the
+ * source Observable so long as each value satisfies the condition defined by
+ * the `predicate`, then completes.
+ */
+export function takeWhile<T>(predicate: (value: T, index: number) => boolean, inclusive = false): MonoTypeOperatorFunction<T> {
+  return operate((source, subscriber) => {
+    let index = 0;
+    source.subscribe(
+      createOperatorSubscriber(subscriber, (value) => {
+        const result = predicate(value, index++);
+        (result || inclusive) && subscriber.next(value);
+        !result && subscriber.complete();
+      })
+    );
+  });
+}