How do I call an Elixir function from a Phoenix LiveView heex template passing arguments with data from socket assigns?

Question

I'm trying to make use of the code in this blog post: [Phoenix LiveView] formatting date/time with local time zone.

I confirmed (with IO.inspect) that his mount and defp code I added to a LiveView adds the socket assigns. But he doesn't give an example of how to call the format_time function from a heex template. Perhaps it should be obvious, but it's not obvious to me. I tried this:

          <%= if connected?(@socket) do
                Cldr.format_time(@auction.started_or_paused_at,
                                 locale: @socket.assigns.locale,
                                 timezone: @socket.assigns.timezone)
              else
                Cldr.format_time(@auction.started_or_paused_at)
              end
          %>

But I get this error:

[error] GenServer #PID<0.655.0> terminating
** (KeyError) key :locale not found in: #Phoenix.LiveView.Socket.AssignsNotInSocket<>
    (ssauction_live 0.1.0) lib/ssauction_live_web/live/auction_live/show.html.heex:32: anonymous fn/2 in SSAuctionWeb.AuctionLive.Show.render/1
...

I guess I can't use the socket assigns while rendering?

assigns inside of template are accessed via @ operator, not by socket.assigns . — Daniel, Dec 27 '21 at 19:46
Thank you [Daniel](https://stackoverflow.com/users/8103819/daniel). If you submit an answer explaining that I'll accept it. — Daryl Spitzer, Dec 27 '21 at 20:40

score 0 · Answer 1 · answered May 25 '22 at 15:33

The socket assigns are available directly inside the template as LiveEEx assigns, such as @foo and @bar. Any assign access should be done using the assigns in the template where proper change tracking takes place.

Here are the official docs: Phoenix.LiveView.Socket.AssignsNotInSocketView

How do I call an Elixir function from a Phoenix LiveView heex template passing arguments with data from socket assigns?

1 Answers1