AshBackpex.Filters.Select (Ash Backpex v0.1.3)

View Source

A Select filter for AshBackpex that renders a dropdown for single-value filtering.

This module provides both the UI rendering (via Backpex.Filters.Select) and the Ash.Expr generation (via AshBackpex.Filters.Filter behavior) for filtering attributes with discrete values like status fields or enum-like string attributes.

Usage

The Select filter is automatically derived for string attributes with one_of constraints when using AshBackpex.LiveResource. You can also use it directly:

defmodule MyApp.Filters.Status do
  use AshBackpex.Filters.Select

  @impl Backpex.Filter
  def label, do: "Status"

  @impl Backpex.Filters.Select
  def prompt, do: "Select status..."

  @impl Backpex.Filters.Select
  def options(_assigns) do
    [
      {"Draft", "draft"},
      {"Published", "published"},
      {"Archived", "archived"}
    ]
  end
end

Filter Values

The filter receives values as a single string:

  • "active" - Filter for records where the field equals "active"
  • "" (empty string) - No filter applied (prompt selected)
  • nil - No filter applied

Options

You must implement the options/1 and prompt/0 callbacks to define the available options and the default prompt text:

@impl Backpex.Filters.Select
def prompt, do: "Select..."

@impl Backpex.Filters.Select
def options(_assigns) do
  [
    {"Label 1", "value1"},
    {"Label 2", "value2"}
  ]
end

Note: Unlike Backpex's Ecto-based filtering which uses the query/3 callback, AshBackpex uses to_ash_expr/3 to generate Ash expressions for filtering.

Summary

Functions

to_ash_expr(field, value, assigns)

Converts a select filter value to an Ash.Expr expression.

Functions

to_ash_expr(field, value, assigns)

Converts a select filter value to an Ash.Expr expression.

Parameters

  • field - The atom name of the attribute being filtered
  • value - The filter value (string or atom from the dropdown selection)
  • assigns - The LiveView assigns (unused by this filter)

Returns

  • Ash.Expr.t() - When a value is selected
  • nil - When no filter should be applied (empty string, nil)

Examples

iex> Select.to_ash_expr(:status, "active", %{})
#Ash.Expr<status == "active">

iex> Select.to_ash_expr(:status, :draft, %{})
#Ash.Expr<status == :draft>

iex> Select.to_ash_expr(:status, "", %{})
nil

iex> Select.to_ash_expr(:status, nil, %{})
nil