Asserts if the given child list contains any duplicate non-null keys.
To invoke this function, use the following pattern, typically in the relevant Widget's constructor:
assert(!debugChildrenHaveDuplicateKeys(this, children));
For a version of this function that can be used in contexts where the list of items does not have a particular parent, see debugItemsHaveDuplicateKeys.
Does nothing if asserts are disabled. Always returns true.
Source
bool debugChildrenHaveDuplicateKeys(Widget parent, Iterable<Widget> children) {
assert(() {
final Key nonUniqueKey = _firstNonUniqueKey(children);
if (nonUniqueKey != null) {
throw new FlutterError(
'Duplicate keys found.\n'
'If multiple keyed nodes exist as children of another node, they must have unique keys.\n'
'$parent has multiple children with key $nonUniqueKey.'
);
}
return true;
});
return false;
}