Base schema for action entities.

Base schema for calculate entities.

Base schema for form entities.

Base schema fields shared by all state entities.

Strictly layer-1/2 keys: name, type, default. Storage-source keys (from:, setter:, encode:, decode:, etc.) are appended by the LiveView and Component DSLs at their layer-2 build sites. Layer-4 keys (optimistic:, animated:) come from Lavash.Optimistic.SchemaExtension.state_schema/0 and are concatenated alongside.

This split is the layering carving from docs/ARCHITECTURE.md punchlist item #3: the base DSL surface shouldn't advertise optimism keys when the user hasn't opted in to layer 4.

Effect entity for actions - runs a side effect function.

MapBy entity for actions — key-based array mutations.

Finds items in an array by a key field and applies a transformation. The @item variable references the matched item in the rx() expression. Return :remove to filter the item out.

PreRun entity for actions — pre-cascade socket-shaped run.

Runs BEFORE the reactive cascade. Use when you need imperative Elixir to compute a state value that downstream calcs depend on:

action :submit do
  pre_run fn socket ->
    # Imperative validation / preprocessing before mutation
    if socket.assigns.form_valid? do
      socket
      |> Lavash.Socket.put_state(:submitted, true)
      |> Lavash.Socket.put_state(:submitted_at, DateTime.utc_now())
    else
      socket
    end
  end
end

After the body returns, the action runtime extracts socket.assigns.__changed__ to populate lavash's dirty set, so the cascade sees what changed and recomputes precisely. So you can use raw Phoenix.Component.assign/3 if you prefer — the cascade will still see the write.

For most state mutation, prefer the declarative set :foo, rx(...).

Argument entity for read and derive blocks.

Run entity for actions — post-cascade socket-shaped run.

Runs AFTER the reactive cascade. Reads settled state; can do socket-level LV ops or external side effects:

action :send do
  run fn socket ->
    new_msg = %{id: next_id(), summary: socket.assigns.summary}
    Phoenix.LiveView.stream_insert(socket, :messages, new_msg)
  end
end

Use for socket-level LV ops (stream_insert/4, allow_upload/3, consume_uploaded_entries/3, cancel_upload/3) or anything that needs the post-cascade view.

Writes from run land in assigns and __changed__ is updated for Phoenix's render diff. BUT lavash does NOT re-fire the cascade — calcs depending on what run wrote are stale until the next event. If you need a derived value of a write, write it in pre_run instead.

Set entity for actions - assigns a value to a state field.

The value can use @field syntax to reference state fields and params, aligned with template syntax:

action :increment do
  set :count, @count + 1
end

action :add_item do
  params [:name]
  set :items, @items ++ [@name]
end

The expression is captured at compile time and can be transpiled to JavaScript for optimistic client-side updates.

Submit entity for actions - submits a form.