Is there any phx-update = "merge" in Phoenix LiveView?

There is the new commit and removed some “Change tracking pitfalls”.
I referred to the comment of @snewcomer

We would essentially need a “snapshot” after JS mounted to be merged in with the server update.

Then I wonder could we update the change with the approach like phx-update = “merge”

old = %{data: %{foo: 123, bar: 456}}
new_changed_foo = %{data: %{foo: 321}}
new_changed_bar = %{data: %{bar: 654}}

Then new_changed_foo update foo: 321 and still keep bar: 456
new_changed_bar update bar:654 and still keep new foo: 321

Looking forward to getting the help.