materio-d8/web/modules/custom/materio_sapi/src/Form/MaterioSapiSearchForm.php

<?php

namespace Drupal\materio_sapi\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Class MaterioSapiSearchForm.
 */
class MaterioSapiSearchForm extends FormBase {


  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'materio_sapi_search_form';
  }

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state) {
    $form['search'] = [
      '#type' => 'textfield',
      // '#title' => $this->t('Search'),
      '#maxlength' => 64,
      '#size' => 25,
      '#weight' => '0',
      '#attributes' => [
        "placeholder" => $this->t('Search'),
        // "@keyup" => "keyup",
        // "@keyup.enter" => "submit",
        "v-model" => "typed",
        "v-focus" => "",
        // "v-on:select" => "typed",
      ],
      '#autocomplete_route_name' => 'materio_sapi.search_autocomplete',

    ];
    $form['searchautocomplete'] = [
      '#type' => 'hidden',
      '#attributes' => [
        "v-model" => "autocomplete"
      ],
    ];
    // $form['submit'] = [
    //   '#type' => 'submit',
    //   '#value' => $this->t('Search'),
    //   '#attributes' => [
    //     '@click.prevent' => "submit",
    //   ]
    // ];
    $form['submit'] = array(
        '#type'   => 'button',
        // '#src'    => '',//drupal_get_path('module', 'materio_search_api') . '/images/search.png',
        '#value'  => t('Search'),
        // '#prefix' => '<div class="search-btn-wrapper">',
        // '#suffix'=> '</div>',
        '#attributes' => [
          'title' => t('Search'),
          '@click.prevent' => "submit",
        ]
      );
    return $form;
  }

  /**
   * {@inheritdoc}
   */
  public function validateForm(array &$form, FormStateInterface $form_state) {
    parent::validateForm($form, $form_state);
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    // Display result.
    foreach ($form_state->getValues() as $key => $value) {
      drupal_set_message($key . ': ' . $value);
    }

  }

}