Meteor Tracker.autorun behavior

Question

Tracker.autorun(() => {
    const data1 = Data1.find().fetch()
    const data2 = Data2.find().fetch()
})

When Data1 changes, the function reruns and data1 is now another array. But what happens with data2? Does it remains exactly the same array (i mean with the same reference)? If it's not, how can I change the behavior so that meteor doesn't call find() again if the data doesn't change?