// Copyright 2018-2025 the Deno authors. MIT license.
// This module is browser compatible.
/** Return type for {@linkcode invert}. */
export type InvertResult<T extends Record<PropertyKey, PropertyKey>> = {
[P in keyof T as T[P]]: P;
};
/**
* Composes a new record with all keys and values inverted.
*
* If the record contains duplicate values, subsequent values overwrite property
* assignments of previous values. If the record contains values which aren't
* {@linkcode PropertyKey}s their string representation is used as the key.
*
* @typeParam T The type of the input record.
*
* @param record The record to invert.
*
* @returns A new record with all keys and values inverted.
*
* @example Basic usage
* ```ts
* import { invert } from "@std/collections/invert";
* import { assertEquals } from "@std/assert";
*
* const record = { a: "x", b: "y", c: "z" };
*
* assertEquals(invert(record), { x: "a", y: "b", z: "c" });
* ```
*/
export function invert<T extends Record<PropertyKey, PropertyKey>>(
record: Readonly<T>,
): InvertResult<T> {
return Object.fromEntries(
Object.entries(record).map(([key, value]) => [value, key]),
);
}
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