9 lines
606 B
TypeScript
9 lines
606 B
TypeScript
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import { Observable } from '../Observable';
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/**
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* Returns an Observable that emits the first item of the source Observable that matches the specified condition.
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* Throws an error if matching element is not found.
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* @param {function} predicate function called with each item to test for condition matching.
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* @returns {Observable} an Observable of the first item that matches the condition.
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*/
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export declare function first<T, R>(predicate?: (value: T, index: number, source: Observable<T>) => boolean, resultSelector?: (value: T, index: number) => R, defaultValue?: R): Observable<T> | Observable<R>;
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