package loncha

func Keys[K comparable, V any](m map[K]V) (keys []K) {

	if m == nil {
		return nil
	}

	keys = make([]K, 0, len(m))
	for k, _ := range m {
		keys = append(keys, k)
	}
	return
}

func Values[K comparable, V any](m map[K]V) (values []V) {

	if m == nil {
		return nil
	}

	values = make([]V, 0, len(m))
	for _, v := range m {
		values = append(values, v)
	}
	return
}

// SelectMap ... rewrite map each key, value pair.
func SelectMap[K comparable, V any](m map[K]V, fn func(k K, v V) (K, V, bool)) (result map[K]V) {
	result = make(map[K]V)
	for k, v := range m {

		nk, nv, remove := fn(k, v)
		if remove {
			continue
		}
		result[nk] = nv
	}
	return
}