es-toolkit/dist/compat/array/countBy.mjs

A state-of-the-art, high-performance JavaScript utility library with a small bundle size and strong type annotations.

import { isArrayLike } from "../predicate/isArrayLike.mjs";
import { iteratee } from "../util/iteratee.mjs";
//#region src/compat/array/countBy.ts
function countBy(collection, iteratee$1) {
	if (collection == null) return {};
	const array = isArrayLike(collection) ? Array.from(collection) : Object.values(collection);
	const mapper = iteratee(iteratee$1 ?? void 0);
	const result = Object.create(null);
	for (let i = 0; i < array.length; i++) {
		const item = array[i];
		const key = mapper(item);
		result[key] = (result[key] ?? 0) + 1;
	}
	return result;
}
//#endregion
export { countBy };