export function computeIfAbsent<K extends WeakKey, V>(map: WeakMap<K, V>, key: K, fn: () => V): V;
export function computeIfAbsent<K, V>(map: Map<K, V>, key: K, fn: () => V): V;
export function computeIfAbsent<K extends string | symbol | number, V>(map: Record<K, V>, key: K, fn: () => V): V;
export function computeIfAbsent(map: any, key: any, fn: () => any): any {
	if (map instanceof Map || map instanceof WeakMap) {
		if (!map.has(key)) {
			map.set(key, fn());
		}
		return map.get(key)!;
	}

	if (!map[key]) {
		map[key] = fn();
	}
	return map[key];
}