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| author | Robin Burchell <robin.burchell@crimson.no> | 2017-01-18 16:26:43 +0100 |
|---|---|---|
| committer | Robin Burchell <robin.burchell@crimson.no> | 2017-03-15 22:11:31 +0000 |
| commit | 34ff6c40c1a03f51bc259e57cffb02ad69c7663b (patch) | |
| tree | acae6098eb50fd44506c404aa2bfc6c40f9ca203 /src/qml/doc | |
| parent | 212ccd59627deb8c06227dbf0f3f3329006c326e (diff) | |
qml: Override the new Object::instanceOf hook to allow QML type checking
[ChangeLog][QtQml] The instanceof keyword in JavaScript has been
extended to work on QML types and instances. This means that you are now
able to use it to verify that a var is indeed the type you expect (e.g.
someVar instanceof Rectangle).
Note that one of the added tests revealed a slight shortcoming in the
QML type system (QTBUG-58477). For now, we should keep consistency and
work to address the problem universally in the future.
Change-Id: I7d9bf9b64cfd037908de1ae51b01065eacb95abe
Task-number: QTBUG-24799
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Diffstat (limited to 'src/qml/doc')
| -rw-r--r-- | src/qml/doc/src/javascript/hostenvironment.qdoc | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/src/qml/doc/src/javascript/hostenvironment.qdoc b/src/qml/doc/src/javascript/hostenvironment.qdoc index 1e33f2f641..7e9a22f5d3 100644 --- a/src/qml/doc/src/javascript/hostenvironment.qdoc +++ b/src/qml/doc/src/javascript/hostenvironment.qdoc @@ -74,6 +74,19 @@ Note that QML makes the following modifications to native objects: \li Locale-aware conversion functions are added to the \l Date and \l Number prototypes. \endlist +In addition, QML also extends the behavior of the instanceof function to +allow for type checking against QML types. This means that you may use it to +verify that a variable is indeed the type you expect, for example: + +\qml + var v = something(); + if (!v instanceof Item) { + throw new TypeError("I need an Item type!"); + } + + ... +\endqml + \section1 JavaScript Environment Restrictions |