How to give a JavaScript function to a qml component [solved]

Hi,
I did a QML component that use a function f(x). It works fine but i would like to give any function to this component as a property ( or another way if this one doesn't work ).
Is there a way to do this and to be able to put several components with diffĂ©rents function on a screen.
Thanks 
It's not clear what you want to achieve.
Can you give us an example of your objective ? 
Hi,
i found it. If my component use f(x) and this component is in a file Draw.qmlSimply do it
@
Draw {
function f(x) {
return Math.cos(x)
}
}
@Have a nice day