Function Flatten

slice/slice.go:475–500

Flatten flattens slice with one level. Play: https://go.dev/play/p/hYa3cBEevtm

(slice any)

// Flatten flattens slice with one level.
// Play: https://go.dev/play/p/hYa3cBEevtm
func Flatten(slice any) any {
	sv := reflect.ValueOf(slice)
	if sv.Kind() != reflect.Slice {
		panic("Flatten: input must be a slice")
	}

	elemType := sv.Type().Elem()
	if elemType.Kind() == reflect.Slice {
		elemType = elemType.Elem()
	}

	result := reflect.MakeSlice(reflect.SliceOf(elemType), 0, sv.Len())

	for i := 0; i < sv.Len(); i++ {
		item := sv.Index(i)
		if item.Kind() == reflect.Slice {
			for j := 0; j < item.Len(); j++ {
				result = reflect.Append(result, item.Index(j))
			}
		} else {
			result = reflect.Append(result, item)
		}
	}

	return result.Interface()
}

// FlattenDeep flattens slice recursive.
// Play: https://go.dev/play/p/yjYNHPyCFaF