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- import { Observable } from '../Observable';
- import { Falsy, OperatorFunction } from '../types';
- import { operate } from '../util/lift';
- import { createFind } from './find';
- export function findIndex<T>(predicate: BooleanConstructor): OperatorFunction<T, T extends Falsy ? -1 : number>;
- /** @deprecated Use a closure instead of a `thisArg`. Signatures accepting a `thisArg` will be removed in v8. */
- export function findIndex<T>(predicate: BooleanConstructor, thisArg: any): OperatorFunction<T, T extends Falsy ? -1 : number>;
- /** @deprecated Use a closure instead of a `thisArg`. Signatures accepting a `thisArg` will be removed in v8. */
- export function findIndex<T, A>(
- predicate: (this: A, value: T, index: number, source: Observable<T>) => boolean,
- thisArg: A
- ): OperatorFunction<T, number>;
- export function findIndex<T>(predicate: (value: T, index: number, source: Observable<T>) => boolean): OperatorFunction<T, number>;
- /**
- * Emits only the index of the first value emitted by the source Observable that
- * meets some condition.
- *
- * <span class="informal">It's like {@link find}, but emits the index of the
- * found value, not the value itself.</span>
- *
- * 
- *
- * `findIndex` searches for the first item in the source Observable that matches
- * the specified condition embodied by the `predicate`, and returns the
- * (zero-based) index of the first occurrence in the source. Unlike
- * {@link first}, the `predicate` is required in `findIndex`, and does not emit
- * an error if a valid value is not found.
- *
- * ## Example
- *
- * Emit the index of first click that happens on a DIV element
- *
- * ```ts
- * import { fromEvent, findIndex } from 'rxjs';
- *
- * const div = document.createElement('div');
- * div.style.cssText = 'width: 200px; height: 200px; background: #09c;';
- * document.body.appendChild(div);
- *
- * const clicks = fromEvent(document, 'click');
- * const result = clicks.pipe(findIndex(ev => (<HTMLElement>ev.target).tagName === 'DIV'));
- * result.subscribe(x => console.log(x));
- * ```
- *
- * @see {@link filter}
- * @see {@link find}
- * @see {@link first}
- * @see {@link take}
- *
- * @param predicate A function called with each item to test for condition matching.
- * @param thisArg An optional argument to determine the value of `this` in the
- * `predicate` function.
- * @return A function that returns an Observable that emits the index of the
- * first item that matches the condition.
- */
- export function findIndex<T>(
- predicate: (value: T, index: number, source: Observable<T>) => boolean,
- thisArg?: any
- ): OperatorFunction<T, number> {
- return operate(createFind(predicate, thisArg, 'index'));
- }
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