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