Default arguments for qml function gives syntax errors

问题

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 ?

回答1:

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).

回答2:

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.

来源：https://stackoverflow.com/questions/44128131/default-arguments-for-qml-function-gives-syntax-errors