Function ref()

Takes an inner value and returns a reactive and
mutable ref object, which has a single property
.value that points to the inner value.

If an object is assigned as a ref’s value, the
object is made deeply reactive with reactive().
This also means if the object contains nested
refs, they will be deeply unwrapped.

To avoid the deep conversion, use shallowRef()
instead.

const count = ref(0)
console.log(count.value) // 0

count.value = 1
console.log(count.value) // 1