std/collections/filter_entries.ts

49 lines
1.2 KiB
TypeScript

// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.
/**
* Returns a new record with all entries of the given record except the ones
* that do not match the given predicate.
*
* @typeParam T The type of the values in the input record.
*
* @param record The record to filter entries from.
* @param predicate The function to test each entry for a condition.
*
* @returns A new record with all entries that match the given predicate.
*
* @example Basic usage
* ```ts
* import { filterEntries } from "@std/collections/filter-entries";
* import { assertEquals } from "@std/assert/assert-equals";
*
* const menu = {
* Salad: 11,
* Soup: 8,
* Pasta: 13,
* };
*
* const myOptions = filterEntries(
* menu,
* ([item, price]) => item !== "Pasta" && price < 10,
* );
*
* assertEquals(myOptions, { Soup: 8 });
* ```
*/
export function filterEntries<T>(
record: Readonly<Record<string, T>>,
predicate: (entry: [string, T]) => boolean,
): Record<string, T> {
const result: Record<string, T> = {};
const entries = Object.entries(record);
for (const [key, value] of entries) {
if (predicate([key, value])) {
result[key] = value;
}
}
return result;
}