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Module

x/rimbu/core/main/index.ts>AsyncReducer.firstWhere

Rimbu is a TypeScript library focused on immutable, performant, and type-safe collections and other tools.
rimbu-org/rimbu
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variable AsyncReducer.firstWhere
import { AsyncReducer } from "https://deno.land/x/rimbu@0.13.1/core/main/index.ts";
const { firstWhere } = AsyncReducer;

Returns an AsyncReducer that remembers the first input value for which the given pred function returns true.

Examples

Example 1

await AsyncStream.from(Stream.range({ amount: 10 })).reduce(AsyncReducer.firstWhere(async v => v > 5)))
// => 6

type

{ <T>(pred: (value: T, index: number) => MaybePromise<boolean>): AsyncReducer<T, T | undefined>; <T, O>(pred: (value: T, index: number) => MaybePromise<boolean>, otherwise: AsyncOptLazy<O>): AsyncReducer<T, T | O>; }