# `Soundcheck.Check.Warning.FormFieldMismatch`
[🔗](https://github.com/leonqadirie/soundcheck/blob/v0.1.0/lib/soundcheck/check/warning/form_field_mismatch.ex#L1)

## Basics

> #### This check is disabled by default. {: .neutral}
>
> [Learn how to enable it](`e:credo:config_file.html#checks`) via `.credo.exs`.

This check has a base priority of `normal` and works with any version of Elixir.

## Explanation

Flags `handle_event/3` clauses whose params pattern requires a form
field the form never sends. The clause cannot match the form's
params, so submitting raises `FunctionClauseError` or falls through
to another clause.

Before:

    <.form for={@form} phx-submit="save">
      <.input field={@form[:email]} />
    </.form>

    def handle_event("save", %{"user" => %{"email" => email, "name" => name}}, socket)

After:

    <.form for={@form} phx-submit="save">
      <.input field={@form[:email]} />
      <.input field={@form[:name]} />
    </.form>

The form's name comes from `to_form(data, as: name)` or from the
schema struct in the changeset (`%MyApp.Accounts.User{}` sends
`user[...]`). Its fields are the keys it reads as `@form[:key]` (or
through `:let`) and literal `name="user[key]"` attributes. The check
stays silent when it cannot resolve the form's name, or when the
form is passed whole to a component that could add fields. Keys
starting with `_` are ignored.

Confidence: medium. Tier: syntactic (works without compiling).

## Check-Specific Parameters

Use the following parameters to configure this check:

### `:excluded_paths`

  Paths to skip (atoms, binaries as path segments, or regexes).

*This parameter defaults to* `[~r/\/test\//, "test"]`.

### `:strict`

  Unused.

*This parameter defaults to* `false`.

## General Parameters

Like with all checks, [general params](`e:credo:check_params.html`) can be applied.

Parameters can be configured via the [`.credo.exs` config file](`e:credo:config_file.html`).

---

*Consult [api-reference.md](api-reference.md) for complete listing*