Indy Forms

Forms can be simplified using IndyForm. A form can be implemented in just couple of lines.

  use IndyForm.FormComponent, context: Context

  form_component(form_key, create_action, update_action, opts)

• form_key: is your schema name. This is used for finding the form in the params.
• create_action: can be an atom or list of atoms. This is used to determine what action should be performed - create or update.
• update_action: can be an atom or list of atoms. This is used to determine what action should be performed - create or update.
  create_action or update_action values can be directly mapped to socket.assigns.live_action values.
• opts: change_listeners can be enabled through opts

  form_component(form_key, create_action, update_action, change_listeners: true)

Example

A complete example which reduces around 50 lines of boilerplate code form component to 3 just lines:

defmodule UserForm do
  alias IndyFormSample.Accounts, as: Context

  use IndyForm.FormComponent, context: Context

  form_component("user", :new, :edit)
end

or can be writen in verbose 7 lines if you prefer this way:

defmodule UserForm do
  alias IndyFormSample.Accounts, as: Context

  use IndyForm.FormComponent, context: Context

  @form_key "user"
  @create_action :new
  @edit_action :edit

  form_component(@form_key, @create_action, @edit_action)
end

Value Change Listeners

on_value_change/2 is invoked when there is a change is detected in field while handling validate event.

key is an atom - which is field name defined in your form.

You can override to handle changes in form happening without writing a single line of javascript.

Note: Don’t forget to enable value change listeners by passing change_listeners: true through form_component opts.

  # handle changes relating to field :contact_me
  def on_value_change(socket, {:contact_me, _old_value, new_value}) do
    show_phone? = show_phone?(new_value)
    show_email? = show_email?(new_value)

    socket
    |> assign(:show_phone, show_phone?)
    |> assign(:show_email, show_email?)
  end

  # needed for handling changes not relating to our fields of interest
  def on_value_change(socket, _), do: socket

Design Goals

Design goals of this library :

• less code injection through macros.
• less magic and more explicit configuration.
• flexibility to override everything to perform one off customizations.
• reduce boilerplate code in application.

You can read docs about forms and contexts.

Browse code at GitHub - lkarthee/indy_form: Simplify LiveView Forms.

And browse sample code here - GitHub - lkarthee/indy_form_sample: A sample project using IndyForm

I want hear more from you - please share feedback or discuss about use cases or suggest design changes.

Note: this library is not published on Hex. You can use it from GitHub. I want to publish after hearing your feedback.

Regards
Kartheek

Edits: changed sample code to reflect few changes.