Errors in Liveview: Parse error ... expected attribute name

Phoenix Forum Questions / Help
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1

I’m stumped. I have a LiveView form tied to a Changeset (rather than a schema) like so:

~H"""
  <.form as={:form} for={@changeset} :let={f} phx-change="validate" phx-submit="save">
    <.input field={f[:email]} />
  </.form>
"""

I can see errors collecting into my changeset on validate. What’s the best pattern for showing an error from the changeset? I see reference to phx-feedback-for and an <.error> helper, but something like this:

<div phx-feedback-for={:email}>
  <.input field={f[:email]} />
  <.error :for={msg <- @changeset.errors}><%%= msg %></.error>
</div>

leaves me with an Parse error ... expected attribute name.

Thank you in advance.

2

An update in case it’s helpful. I can certainly pattern match like:

<.error :for={{:email, {error_msg, _}} <- @changeset.errors}>
  <%= error_msg %>
</.error>

However, I suspect I’m still doing something wrong. The docs for phx-feedback-for seem to indicate that wrapping my error with a field value like :email would filter errors just for that field. But I have to explicitly match on :email to avoid multiple error messages appearing in one spot. It just feels a bit cumbersome or redundant, but it works.

1 Like
3

That’s because the input component from the generated core components uses the field scoped @errors rather than the entire form’s @changeset.errors. It then uses these input field specific errors to render error components within the input component itself.

  def input(%{field: %Phoenix.HTML.FormField{} = field} = assigns) do
    assigns
    |> assign(field: nil, id: assigns.id || field.id)
    |> assign(:errors, Enum.map(field.errors, &translate_error(&1)))
    ...
  end
1 Like
4

That makes sense. Now I can see where @errors is coming from — assigns(:errors ...) in the core component. Thank you.