javascript - Default arguments for qml function gives syntax errors - Stack Overflow

This code works fine in browser hosted JavaScript environment :

    function foo(a=true)
    {
        console.log(a)
    }

But doing the same in qml is giving syntax error.

What might I be doing wrong ?

This code works fine in browser hosted JavaScript environment :

    function foo(a=true)
    {
        console.log(a)
    }

But doing the same in qml is giving syntax error.

What might I be doing wrong ?

• javascript
• qt
• qml

Share Improve this question Follow asked May 23, 2017 at 7:15 Amit TomarAmit Tomar 4,85877 gold badges5353 silver badges8686 bronze badges

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2 Answers 2

Sorted by: Reset to default 11

In QML, you should write the function as

function foo(a) {
    if (a === undefined) a = true

    console.log(a)
}

The syntax

function foo(a=true)

is not supported as this syntax was introduced in ECMA-262 6th edition while QML only implements the fifth edition (as of Qt 5.11).

From Qt 5.12, this code will work fine. See release note.

• The JavaScript engine now supports ECMAScript 7

Hope this will help people in the future.