@monstermann/fn/dist/option/mapOrElse.js

A utility library for TypeScript.

import { dfdlT } from "@monstermann/dfdl";

//#region src/option/mapOrElse.ts
/**
* `mapOrElse(target, map, orElse)`
*
* Applies a mapping function to a value if it's not `null` or `undefined`, otherwise calls a fallback function. If the target value is `null` or `undefined`, it calls the `orElse` function and returns its result. Otherwise, it applies the mapping function and returns the result.
*
* ```ts
* mapOrElse(
*     5,
*     (x) => x * 2,
*     () => 0,
* ); // 10
*
* mapOrElse(
*     null,
*     (x) => x * 2,
*     () => 0,
* ); // 0
*
* mapOrElse(
*     undefined,
*     (x) => x * 2,
*     () => -1,
* ); // -1
* ```
*
* ```ts
* pipe(
*     5,
*     mapOrElse(
*         (x) => x * 2,
*         () => 0,
*     ),
* ); // 10
*
* pipe(
*     null,
*     mapOrElse(
*         (x) => x * 2,
*         () => 0,
*     ),
* ); // 0
* ```
*/
const mapOrElse = dfdlT((target, map, orElse) => {
	if (target == null) return orElse();
	return map(target);
}, 3);

//#endregion
export { mapOrElse };