Lavash.Optimistic (Lavash v0.3.0-rc.1)

Namespace module for Lavash's optimistic update infrastructure.

This module serves as documentation and namespace for the optimistic update system. The actual functionality is provided by submodules:

Active Submodules

• Lavash.Optimistic.Macros - Provides the optimistic_action/3 macro for LiveViews
• Lavash.Optimistic.ActionMacro - Provides optimistic_action for components
• Lavash.Optimistic.Transformers.ExtractColocatedJs - Extracts generated JS to colocated files
• Lavash.Optimistic.Transformers.ExpandAnimatedStates - Expands animated state DSL
• Lavash.Optimistic.Transformers.ExpandDefrx - Expands defrx function calls

How Optimistic Updates Work

When you mark state fields and derives with optimistic: true, Lavash:

1. Generates JavaScript from your DSL action declarations at compile time
2. Extracts to colocated files via Lavash.Optimistic.Transformers.ExtractColocatedJs
3. Injects state into the page via Lavash.LiveView.Runtime.wrap_render/3
4. Updates DOM via the LavashOptimistic hook (in priv/static/lavash_optimistic.js)

Usage Example

defmodule MyApp.CounterLive do
  use Lavash.LiveView

  state :count, :integer, from: :url, default: 0, optimistic: true

  optimistic_action :increment, :count,
    run: fn count, _params -> count + 1 end

  render fn assigns ->
    ~H"""
    <div>
      <span>{@count}</span>
      <button phx-click="increment">+</button>
    </div>
    """
  end
end

The LavashOptimistic hook automatically intercepts the button click, updates the DOM optimistically, then confirms with the server.