description

# checkValidIndex static method

int checkValidIndex(

1. int index,
2. dynamic indexable, [
3. String? name,
4. int? length,
5. String? message,

])

Check that `index` is a valid index into an indexable object.

Throws if `index` is not a valid index into `indexable`.

An indexable object is one that has a `length` and an index-operator `[]` that accepts an index if `0 <= index < length`.

If `name` or `message` are provided, they are used as the parameter name and message text of the thrown error. If `name` is omitted, it defaults to `"index"`.

If `length` is provided, it is used as the length of the indexable object, otherwise the length is found as `indexable.length`.

Returns `index` if it is a valid index.

## Implementation

    static int checkValidIndex(
      int index,
      dynamic indexable, [
      String? name,
      int? length,
      String? message,
    ]) {
      length ??= (indexable.length as int);
      return IndexError.check(
        index,
        length,
        indexable: indexable,
        name: name,
        message: message,
      );
    }