I am trying to connect and disconnect signals of qml in .js.

In this function I am creating objects of qml and establishing connection by writing this line

mainrow.children[1].tvclicked.connect(onTvclicked);

function finishComponentCreation()
{var groupLength=4;

    console.log("inside finishcomp")
    compcreate=comp.createObject(parentID,{"iCompID":0})


    tvfourCreation=buttons.createObject(mainrow,{"iCompID":1,"strText":"TV","value":100})
        mainrow.children[1].tvclicked.connect(onTvclicked); ///**connect**

    fourCreation=buttons.createObject(mainrow,{"iCompID":2,"strText":"RR","value":100})
    fourCreation=buttons.createObject(mainrow,{"iCompID":3,"strText":"I:E","value":100})
    fourCreation=buttons.createObject(mainrow,{"iCompID":4,"strText":"PEEP","value":100})

    moreSetCrt=moreSetting.createObject(mainrow,{"iCompID":5})

}

However I want to disconnect connection on certain event so I wrote another function

function changes(mode)
{
console.log("changes--->"+mode)
    if(mode==="PCV")
    {console.log("########################")
    mainrow.children[1]. tvclicked.disconnect(onTvclicked) // here i am trying to disconnect that connection
     mainrow.children[1]. tvclicked.connect(onRRclicked)// new connection conected to different function
    }
}

but I am unable to disconnect ...this is not working mainrow.children[1]. tvclicked.disconnect(onTvclicked)

why it is not getting disconnected?