math_parser.module

<?php

/**
 * Implements hook_theme().
 *
 * @return array
 */
function math_parser_theme($existing, $type, $theme, $path) {
  $template_params = ['formula' => NULL, 'result' => NULL, 'delta' => NULL];
  return [
    'formula_formatter_react' => [
      'variables' => $template_params,
      'template' => 'formula-formatter-react',
    ],
    'formula_formatter_twig' => [
      'variables' => $template_params,
      'template' => 'formula-formatter-twig',
    ],
    'field__math_parser' => [
      'template' => 'field/field--math-parser',
      'base hook' => 'field',
    ],
  ];
}

/**
 * Implements hook_preprocess_HOOK().
 *
 * @param $variables
 */
function math_parser_preprocess_field__math_parser(&$variables) {

  if ($node = \Drupal::request()->attributes->get('node')) {
    $nid = $node->id();

    if (isset($variables['items'])) {
      $attributes = $variables['items'][0]['attributes'];
      $attributes->setAttribute('id', 'math_parser_list_' . $nid . '_' . $variables['field_name']);
      $attributes->setAttribute('data-nid', $nid);
      $attributes->addClass('math-parser-list');
      $variables['items'][0]['attributes'] = $attributes;
    }
  }
}