prefer-non-var-properties.qdoc

Go to the documentation of this file.

// Copyright (C) 2026 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
/*!
\page qmllint-warnings-and-errors-prefer-non-var-properties.html
\ingroup qmllint-warnings-and-errors
 
\title Prefer non-var properties
\brief [prefer-non-var-properties] Prefer non-var properties over var properties.
 
\qmllintwarningcategory prefer-non-var-properties
 
\section1 Prefer more specific type over var
 
\section2 What happened?
You defined a property in QML with type \c{var} instead of a more specific one,
like \c{int} or \c{string} for example.
 
\section2 Why is that bad?
This affects the readability of the code and the QML tooling can't apply specific
type optimizations.
 
You should avoid using \c{var} as property type for properties that always holds
the same type. To avoid false positives, qmllint only warns about readonly
properties with simple bindings. In other cases, it may not be able to
distinguish properties that have to be var, because they need to hold multiple types,
from properties that always hold the same type.
 
\section2 Example
\qml
import QtQuick
 
Item {
    readonly property var myP: 42
}
\endqml
To fix this warning, replace \c{var} with the specific type.
\qml
import QtQuick
 
Item {
    readonly property int myP: 42
}
\endqml
*/