Flatten List in Golang

1. Basic pattern

func flattenList(input []any) []any {
	res := []any{}
	for _, v := range input {
		if nest, ok := v.([]any); ok {
			res = append(res, flattenList(nest)...)
		} else {
			res = append(res, v)
		}
	}
	return res
}

2. Flatten list to nth level(n=0,1,…), and starts with start

// flattenList flats the list to nth level starts with 0
func flattenListWithLevel(input []any, n int, start int) []any {
	res := []any{}
	for _, v := range input {
		if nest, ok := v.([]any); ok && start < n {
			res = append(res, flattenList(nest, n, start+1)...)
		} else {
			res = append(res, v)
		}
	}
	return res
}