shahryarjb

How to track the variable is being properly changed in LiveView

I created an issue in LiveView GitHub: When `live_flash` is clicked, it cleans `temporary_assigns` inside a `live_component` · Issue #1960 · phoenixframework/phoenix_live_view · GitHub

My problem comes when I click on a live_flash.

I described in this video

And Jose told me:

This is intentional. if you declare something as temporary it will be cleared immediately after rendering and any other event won’t have that date anymore. You need to make sure that the variable is being properly changed tracked so it is not rerendered unless the variable itself changes.

But I could not understand how to track my variable. All the things work but when a user click on live_flash it clears all the temporary_assigns.

Thank you

11 comments

/phoenix #liveview #livecomponents

0 1946 11

2022-04-12 21:43:30 UTC

Most Liked

benwilson512

Author of Craft GraphQL APIs in Elixir with Absinthe

Can you use a regular assign then not a temporary assign?

2

Post #2

benwilson512

Author of Craft GraphQL APIs in Elixir with Absinthe

Can you elaborate on what those problems are?

2

Post #6

tfwright

Sorry, I was having a hard time understanding the exact nature of your use case. FWIW, I have rarely needed to use temporary_assigns because reloading a paginated set of db records is not usually a very expensive operation. And if it is, you can manually manage the list in other ways. If I am not misunderstanding, it sounds like, as others have pointed out, you have been using temporary_assigns for something it was not intended for and may have been only accidentally working. So if you want to avoid hooks you possibly can just switch to assigns?

2

Post #10

Last Post!

cmo

When you don’t need that data anymore. So you’re either happy to fetch it again or you don’t need it because your pre/appending to the list. See below for the append case.

github.com/chrismccord/phoenix_live_view_example

lib/demo_web/live/user_live/index_auto_scroll.ex

defmodule DemoWeb.UserLive.Row do
  use Phoenix.LiveComponent

  defmodule Email do
    use Phoenix.LiveComponent

    def mount(socket) do
      {:ok, assign(socket, count: 0)}
    end

    def render(assigns) do
      ~L"""
      <span id="<%= @id %>" phx-click="click" phx-target="#<%= @id %>" phx-hook="Test">
        Email: <%= @email %> <%= @count %>
      </span>
      """
    end

    def handle_event("click", _, socket) do
      {:noreply, update(socket, :count, &(&1 + 1))}

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