Usage

const a = { a: 1, b: 2, c: 3 };
mapValues(a, (value, key) => value * 2); // => { a: 2, b: 4, c: 6 }

Installation

CLI

npx atmx add helper map-values

Manually

Copy and paste the following method into @/utils/helpers/mapValues.ts:

/**
* Map over all the keys to create a new object.
*
* @example
* const a = { a: 1, b: 2, c: 3 }
* mapValues(a, (value, key) => value * 2) // => { a: 2, b: 4, c: 6 }
*/
export function mapValues<
TValue,
TKey extends string | number | symbol,
TNewValue,
>(
obj: { [K in TKey]: TValue },
mapFunc: (value: TValue, key: TKey) => TNewValue,
): { [K in TKey]: TNewValue };

// This overload exists to support cases where `obj` is a partial
// object whose values are never undefined when the key is also
// defined. For example:
//   { [key: string]?: number } versus { [key: string]: number | undefined }
export function mapValues<
TValue,
TKey extends string | number | symbol,
TNewValue,
>(
obj: { [K in TKey]?: TValue },
mapFunc: (value: TValue, key: TKey) => TNewValue,
): { [K in TKey]?: TNewValue };

export function mapValues<
TValue,
TKey extends string | number | symbol,
TNewValue,
>(
obj: { [K in TKey]?: TValue },
mapFunc: (value: TValue, key: TKey) => TNewValue,
): Record<TKey, TNewValue> {
const keys = Object.keys(obj) as TKey[];
return keys.reduce(
(acc, key) => {
  acc[key] = mapFunc(obj[key]!, key);
  return acc;
},
{} as Record<TKey, TNewValue>,
);
}