Module

std/collections/mod.ts>mapKeys

Deno standard library
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function mapKeys
import { mapKeys } from "https://deno.land/std@0.167.0/collections/mod.ts";

Applies the given transformer to all keys in the given record's entries and returns a new record containing the transformed entries.

If the transformed entries contain the same key multiple times, only the last one will appear in the returned record.

Examples

Example 1

import { mapKeys } from "https://deno.land/std@0.167.0/collections/map_keys.ts";
import { assertEquals } from "https://deno.land/std@0.167.0/testing/asserts.ts";

const counts = { a: 5, b: 3, c: 8 };

assertEquals(
  mapKeys(counts, (it) => it.toUpperCase()),
  {
    A: 5,
    B: 3,
    C: 8,
  },
);

Parameters

record: Readonly<Record<string, T>>
transformer: (key: string) => string

Returns

Record<string, T>