@monstermann/fn/dist/map/getOrThrow.js

A utility library for TypeScript.

import { FnError } from "../function/FnError.js";
import { dfdlT } from "@monstermann/dfdl";

//#region src/map/getOrThrow.ts
/**
* `getOrThrow(map, key)`
*
* Gets the value associated with `key` from `map`, throwing an error if the key doesn't exist or the value is nullable.
*
* ```ts
* getOrThrow(
*     new Map([
*         ["a", 1],
*         ["b", 2],
*     ]),
*     "a",
* ); // 1
*
* getOrThrow(
*     new Map([
*         ["a", 1],
*         ["b", null],
*     ]),
*     "b",
* ); // throws FnError
*
* getOrThrow(
*     new Map([
*         ["a", 1],
*         ["b", 2],
*     ]),
*     "c",
* ); // throws FnError
* ```
*
* ```ts
* pipe(
*     new Map([
*         ["a", 1],
*         ["b", 2],
*     ]),
*     getOrThrow("a"),
* ); // 1
*
* pipe(
*     new Map([
*         ["a", 1],
*         ["b", null],
*     ]),
*     getOrThrow("b"),
* ); // throws FnError
*
* pipe(
*     new Map([
*         ["a", 1],
*         ["b", 2],
*     ]),
*     getOrThrow("c"),
* ); // throws FnError
* ```
*/
const getOrThrow = dfdlT((target, key) => {
	const value = target.get(key);
	if (value != null) return value;
	throw new FnError(`Map.getOrThrow: Value not found.`, [target, key]);
}, 2);

//#endregion
export { getOrThrow };