The LiveSelect component is rendered by calling the live_select/3 function and passing it a form and the name of the field. LiveSelect creates a text input field in which the user can type text, and hidden input field(s) that will contain the value of the selected option(s). As the input text changes, LiveSelect will render a dropdown below the text input containing the matching options, which the user can then select.

Selection can happen either using the keyboard, by navigating the options with the arrow keys and then pressing enter, or by clicking an option with the mouse.

Whenever an option is selected, LiveSelect will trigger a standard phx-change event in the form. See the "Examples" section below for details on how to handle the event.

In single mode, if the configuration option allow_clear is set, the user can manually clear the selection by clicking on the x button on the input field. In tags mode, single tags can be removed by clicking on them.

single-mode

Single mode

tags-mode

Tags mode

options

Options

You can pass or update the list of options the user can choose from with the options assign. Each option will be assigned a label, which will be shown in the dropdown, and a value, which will be the value of the LiveSelect input when the option is selected.

options can be any enumeration of the following elements:

• atoms, strings or numbers: In this case, each element will be both label and value for the option
• tuples: {label, value} corresponding to label and value for the option
• maps: %{label: label, value: value} or %{value: value}
• keywords: [label: label, value: value] or [value: value]

In the case of maps and keywords, if only value is specified, it will be used as both value and label for the option.

Because you can pass a list of tuples, you can use maps and keyword lists to pass the list of options, for example:

%{Red: 1, Yellow: 2, Green: 3}

Will result in 3 options with labels :Red, :Yellow, :Green and values 1, 2, and 3.

Note that the option values, if they are not strings, will be JSON-encoded. Your LiveView will receive this JSON-encoded version in the phx-change and phx-submit events.

alternative-tag-labels

Alternative tag labels

Sometimes, in :tags mode, you might want to use alternative labels for the tags. For example, you might want the labels in the tags to be shorter in order to save space. You can do this by specifying an additional tag_label key when passing options as map or keywords. For example, passing these options:

[%{label: "New York", tag_label: "NY"}, %{label: "Barcelona", tag_label: "BCN"}]  

will result in "New York" and "Barcelona" being used for the options in the dropdown, while "NY" and "BCN" will be used for the tags.

reacting-to-user-s-input

Reacting to user's input

Whenever the user types something in the text input, LiveSelect sends a LiveSelect.ChangeMsg.t/0 message to your LiveView. The message has a text property containing the current text entered by the user, as well as id and field properties with the id of the LiveSelect component and the name of the LiveSelect form field, respectively. The LiveView's job is to handle_info/2 the message and then call LiveView.send_update/3 to update the list of selectable options. See the "Examples" section below for details.

multiple-selection-with-tags-mode

Multiple selection with tags mode

When :tags mode is enabled LiveSelect allows the user to select multiple entries. The entries will be visible above the text input field as removable tags.

The selected entries will be passed to your live view's change and submit event handlers as a list of entries, just like an HTML <select> element with multiple attribute would do.

clearing-the-selection-programmatically

Clearing the selection programmatically

You can clear the selection programmatically by sending a clear: true assign to LiveSelect

send_update(LiveSelect.Component, id: live_select_id, clear: true)

To set a custom id for the component, use the id option when calling live_select/3.

examples

Examples

These examples describe all the moving parts in detail. You can see these examples in action, see which messages and events are being sent, and play around with the configuration easily with the showcase app.

single-mode-1

Single mode

The user can search for cities. The LiveSelect main form input is called city_search. When a city is selected, the coordinates of that city will be the value of the form input. The name of the selected city is available in the text input field named city_search_text_input.

Template:

<.form for={:my_form} :let={f} phx-change="change">
  <%= live_select f, :city_search %> 
</.form>

LiveView:

import LiveSelect

@impl true
def handle_info(%LiveSelect.ChangeMsg{} = change_msg, socket) do 
    cities = City.search(change_msg.text)
    # cities could be:
    # [ {"city name 1", [lat_1, long_1]}, {"city name 2", [lat_2, long_2]}, ... ]
    #
    # but it could also be (no coordinates in this case):
    # [ "city name 1", "city name 2", ... ]
    #
    # or:
    # [ [label: "city name 1", value: [lat_1, long_1]], [label: "city name 2", value: [lat_2, long_2]], ... ] 
    #
    # or even:
    # ["city name 1": [lat_1, long_1], "city name 2": [lat_2, long_2]]

    send_update(LiveSelect.Component, id: change_msg.id, options: cities)
  
    {:noreply, socket}
end

@impl true
def handle_event(
    "change",
    %{"my_form" => %{"city_search_text_input" => city_name, "city_search" => city_coords}},
    socket
  ) do
    IO.puts("You selected city #{city_name} located at: #{city_coords}")

    {:noreply, socket}
end  

tags-mode-1

Tags mode

Let's say you want to build on the previous example and allow the user to select multiple cities and not only one. The :tags mode allows you to do exactly this.

Template:

<.form for={:my_form} :let={f} phx-change="change">
  <%= live_select f, :city_search, mode: :tags %> 
</.form>

LiveView:

@impl true
def handle_event(
    "change",
    %{"my_form" => %{"city_search" => list_of_coords}},
    socket
  ) do
  # list_of_coords will contain the list of the JSON-encoded coordinates of the selected cities, for example:
  # ["[-46.565,-23.69389]", "[-48.27722,-18.91861]"]    

  IO.puts("You selected cities located at: #{list_of_coords}")

  {:noreply, socket}
end  

multiple-liveselect-inputs-in-the-same-liveview

Multiple LiveSelect inputs in the same LiveView

If you have multiple LiveSelect inputs in the same LiveView, you can distinguish them based on the field or id. For example:

Template:

<.form for={:my_form} :let={f} phx-change="change">
  <%= live_select f, :city_search %> 
  <%= live_select f, :album_search %>
</.form>

LiveView:

@impl true
def handle_info(%LiveSelect.ChangeMsg{} = change_msg, socket) do
  options =
    case change_msg.field do
      :city_search -> City.search(change_msg.text)
      :album_search -> Album.search(change_msg.text)
    end

  send_update(LiveSelect.Component, id: change_msg.id, options: options)

  {:noreply, socket}
end