I am trying to check the type of a property at runtime:

Node {
    id: root

    property string foo
    property color diffuseColor
    ...
}

(because I am setting it dynamically from a JS object like {foo: "bar", diffuseColor: [0.5, 1, 0]} only that colors are given in an incompatible format, so a simple assignment would not work.

I need code like:

var targetObject = ... // the QML object
for(var k in jsobj) {
    if(isColorProperty(targetObject[k]))
        targetObject[k] = Qt.rgba(jsobj[k][0], jsobj[k][1], jsobj[k][2], 1)
    else
        targetObject[k] = jsobj[k]
}

to implement that isColorProperty() I tried many different approaches, such as using instanceof (type error), checking Object.getPrototypeOf result (type error), using .toString() (only returns an HTML color string) none of those worked.