Backpex.Filters.Select behaviour (Backpex v0.18.0)

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The select filter renders a select box for the implemented options/1 and prompt/0 callbacks. The prompt/0 callback defines the key for the nil value added as first option.

See the following example for an implementation of an event status filter.

defmodule MyAppWeb.Filters.EventStatusSelect do
  use Backpex.Filters.Select

  @impl Backpex.Filter
  def label, do: "Event status"

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

  @impl Backpex.Filters.Select
  def options(_assigns), do: [
    {"Open", :open},
    {"Close", :close},
  ]

  @impl Backpex.Filter
  def query(query, attribute, value) do
      where(query, [x], field(x, ^attribute) == ^value)
  end
end

use Backpex.Filters.Select

When you use Backpex.Filters.Select, the Backpex.Filters.Select module will set @behavior Backpex.Filters.Select. In addition it will add a render and render_form function in order to display the corresponding filter.

Summary

Callbacks

options(assigns)

The list of options for the select filter.

prompt()

The select's default option.

Functions

changeset(changeset, field, options)

Validates that the selected value exists in the options list.

option_value_to_label(options, value)

Finds the label for a given option value.

query(query, attribute, value, assigns)
render(assigns)
render_form(assigns)
selected(value)

Converts empty string to nil, returns other values as-is.

Callbacks

options(assigns)

@callback options(assigns :: map()) :: [{String.t() | atom(), String.t() | atom()}]

The list of options for the select filter.

prompt()

@callback prompt() :: String.t() | atom()

The select's default option.

Functions

changeset(changeset, field, options)

Validates that the selected value exists in the options list.

Returns the changeset unchanged if the value is valid, or adds an error if not found in options. Empty string is allowed as it represents the "no selection" state.

option_value_to_label(options, value)

Finds the label for a given option value.

Returns nil if the value is not found.

Examples

iex> options = [{"Open", :open}, {"Closed", :closed}]
iex> Backpex.Filters.Select.option_value_to_label(options, "open")
"Open"

iex> options = [{"Open", :open}]
iex> Backpex.Filters.Select.option_value_to_label(options, :open)
"Open"

iex> options = [{"Open", :open}]
iex> Backpex.Filters.Select.option_value_to_label(options, "unknown")
nil

iex> options = [{"Active", "active"}, {"Inactive", "inactive"}]
iex> Backpex.Filters.Select.option_value_to_label(options, "active")
"Active"

iex> options = [{"Active", "active"}]
iex> Backpex.Filters.Select.option_value_to_label(options, :active)
"Active"

iex> Backpex.Filters.Select.option_value_to_label([], "value")
nil

query(query, attribute, value, assigns)

render(assigns)

Attributes

  • value (:any) (required)
  • options (:list) (required)

render_form(assigns)

Attributes

  • form (:any) (required)
  • field (:atom) (required)
  • value (:any) (required)
  • options (:list) (required)
  • prompt (:string) (required)
  • errors (:list) - Defaults to [].

selected(value)

Converts empty string to nil, returns other values as-is.

Examples

iex> Backpex.Filters.Select.selected("")
nil

iex> Backpex.Filters.Select.selected("open")
"open"

iex> Backpex.Filters.Select.selected(:open)
:open

iex> Backpex.Filters.Select.selected(1)
1