@monstermann/fn/dist/object/evolve.js

A utility library for TypeScript.

import { is } from "../function/is.js";
import { dfdlT } from "@monstermann/dfdl";
import { cloneObject } from "@monstermann/remmi";

//#region src/object/evolve.ts
/**
* `evolve(target, props)`
*
* Creates a new object with multiple properties transformed by their corresponding functions in the `props` object.
*
* ```ts
* evolve(
*     { a: 1, b: 2, c: 3 },
*     {
*         a: (x) => x * 2,
*         c: (x) => x + 1,
*     },
* ); // { a: 2, b: 2, c: 4 }
* ```
*
* ```ts
* pipe(
*     { a: 1, b: 2, c: 3 },
*     evolve({
*         a: (x) => x * 2,
*         c: (x) => x + 1,
*     }),
* ); // { a: 2, b: 2, c: 4 }
* ```
*/
const evolve = dfdlT((target, evolver) => {
	let result;
	for (const key in evolver) {
		const value = evolver[key];
		const prev = target[key];
		const next = typeof value === "function" ? value(prev) : evolve(prev, value);
		if (is(prev, next)) continue;
		result ??= cloneObject(target);
		result[key] = next;
	}
	return result ?? target;
}, 2);

//#endregion
export { evolve };