eval.qdoc

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// 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-eval.html
\ingroup qmllint-warnings-and-errors
 
\title Eval
\brief [eval] Usage of eval.
 
\qmllintwarningcategory eval
 
\section1 Do not use eval
 
\section2 What happened?
You used \c {eval} in your code.
 
\section2 Why is that bad?
The \c{eval} method is slow and potentially dangerous. \c{eval} executes its
argument as if it were its own JavaScript script, which adds some overhead to the
execution. The argument passed to \c{eval} is potentially a vector for remote
code execution attacks.
 
\section2 Example
\qml
import QtQuick
 
Item {
    function f() {
        let myString = "x",
        myObject = {
            x: 10
        },
        value = eval("myObject." + myString);
    }
}
\endqml
To fix this warning, rewrite the code so that it doesn't contain any \c {eval}
calls.
\qml
import QtQuick
 
Item {
    function f() {
        let myString = "x",
        myObject = {
            x: 10
        },
        value = myObject[myString];
    }
}
\endqml
*/