Wordpress Custom Routes

<?php

add_action('rest_api_init', 'universityRegisterSearch');

function universityRegisterSearch(){
    register_rest_route('university/v1', 'search', [
        'methods' => WP_REST_Server::READABLE, // Wordpress alias for the GET method (we could write also GET)
        'callback' => 'universitySearchResults', // callback name of a function that we will use
    ]);
}

// The callback function
function universitySearchResults($data) {
    $mainQuery = new WP_Query(array(
      'posts_per_page' => -1,
      'post_type' => array('post', 'page', 'professor', 'program', 'campus', 'event'),
      's' => sanitize_text_field($data['term'])
    ));

    $results = array(
      'generalInfo' => array(),
      'professors' => array(),
      'programs' => array(),
      'events' => array(),
      'campuses' => array()
    );

    while($mainQuery->have_posts()) {
      $mainQuery->the_post();

      if (get_post_type() == 'post' OR get_post_type() == 'page') {
        array_push($results['generalInfo'], array(
          'title' => get_the_title(),
          'permalink' => get_the_permalink(),
          'postType' => get_post_type(),
          'authorName' => get_the_author()
        ));
      }

      if (get_post_type() == 'professor') {
        array_push($results['professors'], array(
          'title' => get_the_title(),
          'permalink' => get_the_permalink(),
          'image' => get_the_post_thumbnail_url(0, 'professorLandscape'), // 0 means the current post
        ));
      }

      if (get_post_type() == 'program') {
        $relatedCampuses = get_field('related_campus');

        if ($relatedCampuses) {
          foreach ($relatedCampuses as $campus) {
            array_push($results['campuses'], [
              'title' => get_the_title($campus),
              'permalink' => get_the_permalink($campus),
            ]);
          }
        }

        array_push($results['programs'], array(
          'title' => get_the_title(),
          'permalink' => get_the_permalink(),
          'id' => get_the_ID(),
        ));
      }

      if (get_post_type() == 'campus') {
        array_push($results['campuses'], array(
          'title' => get_the_title(),
          'permalink' => get_the_permalink()
        ));
      }

      if (get_post_type() == 'event') {
        $eventDate = new DateTime(get_field('event_date'));
        $month = $eventDate->format('M');
        $day = $eventDate->format('d');
        array_push($results['events'], array(
          'title' => get_the_title(),
          'permalink' => get_the_permalink(),
          'month' => $month,
          'day' => $day,
          'excerpt' => has_excerpt() ? get_the_excerpt() : wp_trim_words(get_the_content(), 18),
         ));
      }

    }

    if ($results['programs']){
      $programsMetaQuery = [
        'relation' =>'OR',
      ];

      foreach($results['programs'] as $item){
        $programsMetaQuery[]= [
          'key' => 'related_programs',
          'compare'=> 'LIKE',
          'value' => '"' . $item['id']. '"',
        ];
      }
      $progamRelationshipQuery = new WP_Query([
        'posts_per_page' => -1,
        'post_type' => [
          'professor',
          'event',
        ],
        'meta_query' => $programsMetaQuery,
      ]);

      while($progamRelationshipQuery->have_posts()){
        $progamRelationshipQuery->the_post();


        if (get_post_type() == 'event') {
          $eventDate = new DateTime(get_field('event_date'));
          $month = $eventDate->format('M');
          $day = $eventDate->format('d');
          array_push($results['events'], array(
            'title' => get_the_title(),
            'permalink' => get_the_permalink(),
            'month' => $month,
            'day' => $day,
            'excerpt' => has_excerpt() ? get_the_excerpt() : wp_trim_words(get_the_content(), 18),
           ));
        }

        if (get_post_type() == 'professor') {
          array_push($results['professors'], array(
            'title' => get_the_title(),
            'permalink' => get_the_permalink(),
            'image' => get_the_post_thumbnail_url(0, 'professorLandscape'), // 0 means the current post
          ));
        }





      }

      // array_values removes the numeric keys from associative array that creates the array_unique
      // array_unique removes the duplicate elements from the array and the SORT_REGULAR creates an associative array
      $results['professors'] = array_values(array_unique($results['professors'], SORT_REGULAR));
      $results['events'] = array_values(array_unique($results['events'], SORT_REGULAR));
    }


    return $results;

  }