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

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A MultiSelect filter for AshBackpex that renders checkboxes for multi-value filtering.

This module provides both the UI rendering (via Backpex.Filters.MultiSelect) and the Ash.Expr generation (via AshBackpex.Filters.Filter behavior) for filtering attributes where the field value should match any of the selected values.

Usage

The MultiSelect filter is automatically derived for array-type attributes with one_of constraints when using AshBackpex.LiveResource. You can also use it directly:

defmodule MyApp.Filters.Tags do
  use AshBackpex.Filters.MultiSelect

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

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

  @impl Backpex.Filters.MultiSelect
  def options(_assigns) do
    [
      {"Bug", "bug"},
      {"Feature", "feature"},
      {"Enhancement", "enhancement"}
    ]
  end
end

Filter Values

The filter receives values as a list of strings:

  • ["value1", "value2"] - Filter for records where field IN ("value1", "value2")
  • [] - No filter applied (none 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.MultiSelect
def prompt, do: "Select..."

@impl Backpex.Filters.MultiSelect
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, values, assigns)

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

Functions

to_ash_expr(field, values, assigns)

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

Parameters

  • field - The atom name of the attribute being filtered
  • value - The filter value (list of strings from checkbox selections)
  • assigns - The LiveView assigns (unused by this filter)

Returns

  • Ash.Expr.t() - When one or more values are selected (field IN [...])
  • nil - When no filter should be applied (empty list, nil)

Examples

iex> MultiSelect.to_ash_expr(:status, ["active", "pending"], %{})
#Ash.Expr<status in ["active", "pending"]>

iex> MultiSelect.to_ash_expr(:status, ["active"], %{})
#Ash.Expr<status in ["active"]>

iex> MultiSelect.to_ash_expr(:status, [], %{})
nil

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