Base schema for action entities.

Base schema for calculate entities.

Base schema for form entities.

Base schema fields shared by all state entities.

LiveView extends this with: :url from option, setter, encode, decode, required Component uses this with: :socket/:ephemeral from option only

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.

Argument entity for read and derive blocks.

Run entity for actions - executes a function that transforms assigns.

Server-only (plain function)

Use this for complex multi-field updates where individual set calls would be cumbersome:

action :checkout do
  run fn assigns ->
    assigns
    |> assign(:status, :processing)
    |> assign(:submitted_at, DateTime.utc_now())
  end
end

Transpilable (with reads)

Add reads to declare state dependencies, enabling JavaScript transpilation for optimistic client-side updates:

action :apply_discount do
  run [:subtotal, :discount_rate], fn assigns ->
    discount = assigns.subtotal * assigns.discount_rate
    final = assigns.subtotal - discount

    assigns
    |> assign(:discount_amount, discount)
    |> assign(:total, final)
  end
end

The reads list declares which state fields the function depends on. This enables the transpiler to generate equivalent JavaScript.

The function receives an assigns map (state + params merged) and should use assign/3 to update fields. This ensures proper change tracking.

For simple single-field updates, prefer set with rx():

action :increment do
  set :count, rx(@count + 1)
end

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.