hvanderheide

Tailwind Form Field components

I’m trying to get some form styling going with tailwind in a (live) view. The approach below works, however the heex template seems to get really cluttered with repetitive code, especially as I introduce error stylings. As tailwind seems generally common within the phoenix world, I thought there might be a tailwind form field renderer already, but I was unable to find one.

 <div class="col-span-6">
  <%= label f, :email, class: ["block text-sm font-medium text-gray-700"] %>
  <div class="mt-1 sm:mt-0 sm:col-span-2 relative rounded-md shadow-sm">
    <%= email_input f, :email, required: true, autocomplete: false, value: @card.email, class: ["mt-1 block w-full shadow-sm sm:text-sm rounded-md"] ++ [(if f.errors[:email], do: "pr-10 border-red-300 text-red-900 placeholder-red-300 focus:outline-none focus:ring-red-500 focus:border-red-500", else: "focus:ring-indigo-500 focus:border-indigo-500 shadow-sm border-gray-300")] %>
    <%= if f.errors[:email] do %>
      <div class="absolute inset-y-0 right-0 pr-3 flex items-center pointer-events-none">
        <svg class="h-5 w-5 text-red-500" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20" fill="currentColor" aria-hidden="true">
          <path fill-rule="evenodd" d="M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7 4a1 1 0 11-2 0 1 1 0 012 0zm-1-9a1 1 0 00-1 1v4a1 1 0 102 0V6a1 1 0 00-1-1z" clip-rule="evenodd" />
        </svg>
      </div>
    <% end %>
  </div>
  <%= if message = f.errors[:email] do %>
    <p class="mt-2 text-sm text-red-600" id="email-error"><%= translate_error(message) %></p>
  <% end %>
</div>

So I was thinking, coming from python webframeworks, I should probably be able to create a FormFieldComponent and hand it the form, field(name, type) and instance to render properly. Without taking fieldsets into account that would probably lead to a template with a bunch of live_component tags.

Is this a good approach, or is there a more common way to do this?

Edit: It seems petal.build kind of solved this problem, although I’m not sure they fully adopted tailwind’s styling (e.g. svg elements seem missing from formfield errors)

15 comments

/phoenix #forms #liveview #tailwindcss

1 3121 15

2024-07-23 16:11:25 UTC

Marked As Solved

chrismccord

Creator of Phoenix

You want to compartmentalize your forms and styling into their own function components. For example, you templates should look something like this:

    <.form let={f} for={@changeset}>
      <.input f={f} field={:email} type="email" value={@card.email} />
      <.input f={f} field={:title} type="text />
    </.form>

and you can define input functions which wraps all your styling and error tags:

  def input(%{type: "email"} = assigns) do
    ~H"""
    <%= label @f, @field, class: ["block text-sm font-medium text-gray-700"] %>
    <div class="mt-1 sm:mt-0 sm:col-span-2 relative rounded-md shadow-sm">
      <%= email_input @f, @field, required: true, autocomplete: false, value: @value, class: ["mt-1 block w-full shadow-sm sm:text-sm rounded-md"] ++ [(if f.errors[:email], do: "pr-10 border-red-300 text-red-900 placeholder-red-300 focus:outline-none focus:ring-red-500 focus:border-red-500", else: "focus:ring-indigo-500 focus:border-indigo-500 shadow-sm border-gray-300")] %>
      <%= if @f.errors[@field] do %>
        <div class="absolute inset-y-0 right-0 pr-3 flex items-center pointer-events-none">
          <svg class="h-5 w-5 text-red-500" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20" fill="currentColor" aria-hidden="true">
            <path fill-rule="evenodd" d="M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7 4a1 1 0 11-2 0 1 1 0 012 0zm-1-9a1 1 0 00-1 1v4a1 1 0 102 0V6a1 1 0 00-1-1z" clip-rule="evenodd" />
          </svg>
        </div>
      <% end %>
    </div>
    """
  end

  def input(%{type: "text"} = assigns) do
    ...
  end

Post #3

Also Liked

chrismccord

Creator of Phoenix

To each their own. With tailwind I never touch css files
No problem going that direction if you want to, but I found function components are enough to avoid duplication that I care about.

Post #5

chrismccord

Creator of Phoenix

yeah to be clear, I’m saying I can de-dup within elixir rather than using css rules, for example using your label_class example and the upcoming 0.18 declarative assigns:

  attr :type, :string, required: true
  attr :label_class, :string, default: "block text-sm font-medium text-gray-700"

Or, you could support an optional <:label> slot which the caller can use to pass whatever they wanted, so you have caller customization options depending on what you want.

Post #7