elixir - How to update the value of nested assigns in LiveView

Question

I’m trying to use nested assigns but cannot find a way to update its values… Imagine I have this:

def mount(socket) do
    socket = assign(socket, state: [value1: "20", value2: "50"])
    {:ok, socket} 
end

How do I update the value here?

def handle_event("dec", _params, socket) do
    socket = assign(socket, state[:value1], "1")
    {:noreply, socket}
end

How do I reference/represent that nested key?

question from:https://stackoverflow.com/questions/65842391/how-to-update-the-value-of-nested-assigns-in-liveview

Answer 1

Kernel.update_in/3 is your friend here.

state = [value1: "20", value2: "50"]
update_in state, [:value1], & &1 <> "updated"
#? [value1: "20updated", value2: "50"]

Sidenote: this question has nothing to do with phoenix-framework.