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std/collections/min_by.ts

The Deno Standard Library
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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * Returns the first element that is the smallest value of the given function or * undefined if there are no elements * * @example * ```ts * import { minBy } from "https://deno.land/std@$STD_VERSION/collections/min_by.ts"; * import { assertEquals } from "https://deno.land/std@$STD_VERSION/assert/assert_equals.ts"; * * const people = [ * { name: "Anna", age: 34 }, * { name: "Kim", age: 42 }, * { name: "John", age: 23 }, * ]; * * const personWithMinAge = minBy(people, (i) => i.age); * * assertEquals(personWithMinAge, { name: "John", age: 23 }); * ``` */export function minBy<T>( array: Iterable<T>, selector: (el: T) => number,): T | undefined;/** * Returns the first element that is the smallest value of the given function or * undefined if there are no elements * * @example * ```ts * import { minBy } from "https://deno.land/std@$STD_VERSION/collections/min_by.ts"; * * const people = [ * { name: "Anna" }, * { name: "Kim" }, * { name: "John" }, * ]; * * const personWithMinName = minBy(people, (i) => i.name); * ``` */export function minBy<T>( array: Iterable<T>, selector: (el: T) => string,): T | undefined;/** * Returns the first element that is the smallest value of the given function or * undefined if there are no elements * * @example * ```ts * import { minBy } from "https://deno.land/std@$STD_VERSION/collections/min_by.ts"; * import { assertEquals } from "https://deno.land/std@$STD_VERSION/assert/assert_equals.ts"; * * const people = [ * { name: "Anna", age: 34n }, * { name: "Kim", age: 42n }, * { name: "John", age: 23n }, * ]; * * const personWithMinAge = minBy(people, (i) => i.age); * * assertEquals(personWithMinAge, { name: "John", age: 23n }); * ``` */export function minBy<T>( array: Iterable<T>, selector: (el: T) => bigint,): T | undefined;/** * Returns the first element that is the smallest value of the given function or * undefined if there are no elements * * @example * ```ts * import { minBy } from "https://deno.land/std@$STD_VERSION/collections/min_by.ts"; * * const people = [ * { name: "Anna", startedAt: new Date("2020-01-01") }, * { name: "Kim", startedAt: new Date("2020-03-01") }, * { name: "John", startedAt: new Date("2019-01-01") }, * ]; * * const personWithMinStartedAt = minBy(people, (i) => i.startedAt); * ``` */export function minBy<T>( array: Iterable<T>, selector: (el: T) => Date,): T | undefined;export function minBy<T>( array: Iterable<T>, selector: | ((el: T) => number) | ((el: T) => string) | ((el: T) => bigint) | ((el: T) => Date),): T | undefined { let min: T | undefined = undefined; let minValue: ReturnType<typeof selector> | undefined = undefined;
for (const current of array) { const currentValue = selector(current);
if (minValue === undefined || currentValue < minValue) { min = current; minValue = currentValue; } }
return min;}