/
map_values.ts
43 lines (39 loc) · 1.09 KB
/
map_values.ts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.
/**
* Applies the given transformer to all values in the given record and returns a
* new record containing the resulting keys associated to the last value that
* produced them.
*
* @example
* ```ts
* import { mapValues } from "https://deno.land/std@$STD_VERSION/collections/map_values.ts";
* import { assertEquals } from "https://deno.land/std@$STD_VERSION/testing/asserts.ts";
*
* const usersById = {
* "a5ec": { name: "Mischa" },
* "de4f": { name: "Kim" },
* };
* const namesById = mapValues(usersById, (it) => it.name);
*
* assertEquals(
* namesById,
* {
* "a5ec": "Mischa",
* "de4f": "Kim",
* },
* );
* ```
*/
export function mapValues<T, O>(
record: Readonly<Record<string, T>>,
transformer: (value: T) => O,
): Record<string, O> {
const ret: Record<string, O> = {};
const entries = Object.entries(record);
for (const [key, value] of entries) {
const mappedValue = transformer(value);
ret[key] = mappedValue;
}
return ret;
}