Formie "New submission" extension

extension.js

/**
 * Implement our custom "New submission" button into the Formie submission index.
 */
(function () {
  const newSubmissionActionUrl = "/admin/actions/site/formie-draft/new";
  const newSubmissionLabel = Craft.t("formie", "New submission");

  Craft.Formie.SubmissionIndex.implement({
    forms: null,
    $newEntryBtn: null,

    init(...args) {
      this.on("selectSource", this.updateButton.bind(this));
      this.on("selectSite", this.updateButton.bind(this)); // not needed yet
      this.base(...args);
    },

    /**
     * Find form sources.
     */
    afterInit() {
      this.forms = Array.from(this.$visibleSources)
        .filter((el) => el.dataset.handle)
        .map((el) => ({
          handle: el.dataset.handle,
          label: el.innerText,
        }));

      this.base();
    },

    /**
     * Update the "New submission" button.
     */
    updateButton() {
      if (!this.$source) {
        return;
      }

      if (this.$newEntryBtn) {
        this.$newEntryBtn.remove();
      }

      const handle = this.$source.data("handle");
      const selected = this.forms.find((form) => form.handle === handle);

      if (selected) {
        this.$newEntryBtn = $("<a>")
          .attr({
            href: `${newSubmissionActionUrl}?handle=${selected.handle}`,
            class: "btn submit add icon",
            role: "button",
            tabindex: 0,
          })
          .text(newSubmissionLabel);

        this.addButton(this.$newEntryBtn);
      }
    },
  });
})();

FormieAsset.php

<?php

namespace site\web\assets\formie;

use craft\web\AssetBundle;
use verbb\formie\web\assets\cp\CpAsset;

class FormieAsset extends AssetBundle
{
	public function init()
	{
		parent::init();

		$this->sourcePath = __DIR__;
		$this->depends = [CpAsset::class];
		$this->js = ['extension.js'];
	}
}

FormieDraftController.php

<?php

namespace site\controllers;

use Craft;
use craft\web\Controller;
use DateTime;
use DateTimeZone;
use Exception;
use verbb\formie\elements\Form;
use verbb\formie\elements\Submission;
use verbb\formie\Formie;
use yii\web\BadRequestHttpException;

class FormieDraftController extends Controller
{
	protected $allowAnonymous = self::ALLOW_ANONYMOUS_NEVER;

	/**
	 * Handle of the status to apply to new drafts.
	 */
	protected $draftStatus = "draft";

	/**
	 * Creates a new submission draft.
	 */
	public function actionNew()
	{
		$this->requireCpRequest();
		$this->requirePermission('formie-editSubmissions');

		$request = Craft::$app->getRequest();

		$handle = $request->getQueryParam("handle");

		/** @var Form */
		$form = Form::find()->handle($handle)->one();

		if (!$form) {
			throw new BadRequestHttpException("No form exists with the handle \"$handle\"");
		}

		$submission = new Submission();
		$submission->setForm($form);
		$submission->siteId = Craft::$app->getSites()->getCurrentSite()->id;

		// Apply a special "draft" status to distinguish from front-end submissions.
		$submission->setStatus(
			Formie::$plugin->getStatuses()->getStatusByHandle($this->draftStatus)
				?? $form->getDefaultStatus()
		);

		// Save IP and user if needed, same as original submit action.
		if ($form->settings->collectIp) {
			$submission->ipAddress = Craft::$app->getRequest()->userIP;
		}
		if ($form->settings->collectUser) {
			if ($user = Craft::$app->getUser()->getIdentity()) {
				$submission->setUser($user);
			}
		}

		// Our title will be the submission timestamp, since no fields have been
		// filled out yet. We use the `afterSaveSubmission` event to update the
		// title of every submission anyway, so this is fine for now.
		if (!$submission->title) {
			$now = new DateTime('now', new DateTimeZone(Craft::$app->getTimeZone()));
			$submission->title = $now->format(DateTime::W3C);
		}

		$success = Craft::$app->getElements()->saveElement($submission, false);

		if (!$success) {
			throw new Exception(Craft::t("formie", "Couldn’t save submission."));
		}

		// We skip triggering events and integrations at this point, since they
		// are not needed for our use case.

		// Redirect to our fresh submission.
		return $this->redirect($submission->getCpEditUrl());
	}
}

Module.php

<?php

namespace site;

use Craft;
use craft\events\TemplateEvent;
use craft\web\View;
use site\web\assets\formie\FormieAsset;
use verbb\formie\elements\Submission;
use yii\base\Event;

class Module extends \yii\base\Module
{
	/**
	 * Initializes the module.
	 */
	public function init(): void
	{
		// Set a @modules alias pointed to the modules/ directory
		Craft::setAlias('@site', __DIR__);

		// Set the controllerNamespace based on whether this is a console or web request
		if (Craft::$app->getRequest()->getIsConsoleRequest()) {
			$this->controllerNamespace = 'site\\console\\controllers';
		} else {
			$this->controllerNamespace = 'site\\controllers';
		}

		parent::init();

		$this->registerFormieExtensions();
	}

	/**
	 * Registers event listeners for the Formie plugin.
	 */
	protected function registerFormieExtensions(): void
	{
		// Update the title according to format whenever a submission was saved.
		// We could add some checks here to only apply to drafts, but I want to
		// keep the submission title in sync with data always.
		Event::on(Submission::class, Submission::EVENT_AFTER_SAVE, function (Event $event) {
			/** @var Submission */
			$submission = $event->sender;

			if (!$event->isNew) {
				$form = $submission->getForm();
				$submission->updateTitle($form);
			}
		});

		// Attach our asset bundle if the Formie's control panel bundle is loaded.
		// The bundle will extend Formie's element index script in order to add
		// the "New submission" button.
		Event::on(View::class, View::EVENT_BEFORE_RENDER_TEMPLATE, function (TemplateEvent $event) {
			$formieCpBundle = "verbb\\formie\\web\\assets\\cp\\CpAsset";
			$loadedBundles = array_keys($event->sender->assetBundles ?? []);

			if (!in_array($formieCpBundle, $loadedBundles)) {
				return;
			}

			$event->sender->registerAssetBundle(FormieAsset::class);

			$event->sender->registerTranslations('formie', [
				'New submission',
			]);
		});
	}
}