Check that a value 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 a and index-operator []
that accepts an index if 0 <= index < length
.
If length
is provided, it is used as the length of the indexable object, otherwise the length is found as indexable.length
.
static void checkValidIndex(int index, var indexable, [String name, int length, String message]) { if (length == null) length = indexable.length; // Comparing with `0` as receiver produces better dart2js type inference. if (0 > index || index >= length) { if (name == null) name = "index"; throw new RangeError.index(index, indexable, name, message, length); } }
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/2.0.0/dart-core/RangeError/checkValidIndex.html