Once I kept repeatedly inputting a character in the search box, it is getting slower and slower until it hangs. I wanted to optimize it and make it smoother.

Can you guys help me or give me any advice for what I should do? I am getting the data correctly it just once I tried to search repeatedly without refreshing the page it is getting laggy.

This is my model:

public class TrieNode
    {
        public List<string> Titles { get; set; }
        public Dictionary<char, TrieNode> Children { get; set; }
        public bool IsEndOfWord { get; set; }
        public int Popularity { get; set; }

        public TrieNode()
        {
            Titles = new List<string>();
            Children = new Dictionary<char, TrieNode>();
        }
    }

This is my service:

public void Insert(string title)
        {
            var node = _trie;
            foreach (var ch in title)
            {
                if (!node.Children.ContainsKey(ch))
                {
                    node.Children[ch] = new TrieNode();
                }
                node = node.Children[ch];
            }

            if (node.Titles != null)
            {
                node.Titles.Add(title);
            }
            else
            {
                node.IsEndOfWord = true;
            }

            if (node.Titles != null && node.Titles.Count >= Threshold)
            {
                ConvertListToTrie(node);
            }
        }

        private void ConvertListToTrie(TrieNode node)
        {
            foreach (var title in node.Titles)
            {
                Insert(title);
            }
            node.Titles = null;
        }

        /* Search to get exact titles and with levenshtein then sort by latest visit first then popularity and titles asc then lastly with levenshtein*/
        public List<(string title, int popularity)> Search(string prefix)
        {
            var node = _trie;
            foreach (var ch in prefix)
            {
                if (!node.Children.ContainsKey(ch))
                {
                    return new List<(string, int)>();
                }
                node = node.Children[ch];
            }
            return GettitlesFromNode(prefix, node);
        }

        private List<(string title, int popularity)> GettitlesFromNode(string prefix, TrieNode node)
        {
            var titles = new List<(string title, int popularity)>();
            if (node.IsEndOfWord)
            {
                titles.Add((prefix, node.Popularity));
            }
            foreach (var child in node.Children.OrderByDescending(c => c.Value.Popularity))
            {
                titles.AddRange(GettitlesFromNode(prefix + child.Key, child.Value));
            }
            return titles;
        }

        public List<(string title, int popularity)> GetSuggestionsWithLevenshtein(string query)
        {
            var exactMatches = Search(query);
            var additionalSuggestions = new List<(string title, int popularity)>();

            if (exactMatches.Count < 10)
            {
                additionalSuggestions = FindSimilarTitles(query)
                    .Select(w => (title: w, popularity: GetPopularityFromTrie(w)))
                    .Where(w => !exactMatches.Any(s => s.title == w.title))
                    .Take(10 - exactMatches.Count)
                    .ToList();
            }

            return exactMatches.Select(s => (s.title, s.popularity))
                    .Concat(additionalSuggestions)
                    .OrderByDescending(s => s.popularity)
                    .ThenBy(s => s.title)
                    .ThenBy(s => Levenshtein(query, s.title))
                    .ToList();
        }

        /* Get Popularity and Last Visit of each title */
        private int GetPopularityFromTrie(string title)
        {
            var node = _trie;
            foreach (var ch in title)
            {
                if (!node.Children.ContainsKey(ch))
                {
                    return 0;
                }
                node = node.Children[ch];
            }
            return node.IsEndOfWord ? node.Popularity : 0;
        }

        /* Find Titles with levenshtein distance */
        private List<string> FindSimilarTitles(string input)
        {
            var results = new List<string>();
            foreach (var title in GetAllTitles(_trie, ""))
            {
                if (Levenshtein(input, title) <= 2)
                {
                    results.Add(title);
                }
            }
            return results;
        }

        public List<string> GetAllTitles(TrieNode node, string prefix)
        {
            var titles = new List<string>();
            if (node.IsEndOfWord)
            {
                titles.Add(prefix);
            }
            foreach (var child in node.Children)
            {
                titles.AddRange(GetAllTitles(child.Value, prefix + child.Key));
            }
            return titles;
        }

        private int Levenshtein(string input, string target)
        {
            if (input == target)
            {
                return 0;
            }

            if (input.Length == 0)
            {
                return target.Length;
            }

            if (target.Length == 0)
            {
                return input.Length;
            }

            int[,] distance = new int[input.Length + 1, target.Length + 1];

            for (int i = 0; i <= input.Length; i++)
            {
                distance[i, 0] = i;
            }

            for (int j = 0; j <= target.Length; j++)
            {
                distance[0, j] = j;
            }

            for (int i = 1; i <= input.Length; i++)
            {
                for (int j = 1; j <= target.Length; j++)
                {
                    int cost = input[i - 1] == target[j - 1] ? 0 : 1;

                    distance[i, j] = Math.Min(Math.Min(distance[i - 1, j] + 1, distance[i, j - 1] + 1), distance[i - 1, j - 1] + cost);
                }
            }
            return distance[input.Length, target.Length];
        }

This is my controller:

static TrieController()
        {
            var titles = System.IO.File.ReadAllLines("./assets/titles.txt");

            foreach (var title in titles)
            {
                if (Regex.IsMatch(title, "^[a-z\s]+$", RegexOptions.IgnoreCase))
                {
                    _trieService.Insert(title.ToLower());
                }
            }
        }

        [HttpGet]
        public IActionResult GetSuggestions(string title)
        {
            var suggestions = _trieService.GetSuggestionsWithLevenshtein(title)
                               .Select(s => new { title = s.title, popularity = s.popularity });
            return Ok(suggestions.Take(10));
        }

This is the app.js:

let visitedTitles = JSON.parse(localStorage.getItem('visitedTitles')) || [];

/* Suggestions */
function getSuggestions()
 {
    const query = $('#search-box').val();
    if (query.length === 0) {
      $('#suggestions').empty();
      return;
    }
  
    $.ajax({
      //url: `http://ec2-3-25-135-98.ap-southeast-2.compute.amazonaws.com/trie/`,
      url: `https://localhost:7223/trie/`,
      data: { title: query },
      success: function (data) {
        displaySuggestions(data);
      }
    });
  
  $('#clear-button').click(function() 
  {
    $('#search-box').val('');
    $('#suggestions').empty();
    $(this).hide(); 
  });
  
  $('#search-box').on('input', function() 
  {
    const query = $(this).val();
    if (query.length > 0) {
      $('#clear-button').show();
    } else {
      $('#clear-button').hide(); 
    }
    getSuggestions();
  });
}

function displaySuggestions(suggestions) 
{
  const suggestionList = $('#suggestions');
  suggestionList.empty();
  
  const sortData = suggestions.map(title => {
    const visitedItem = visitedTitles.find(item => item.title === title.title);
    return {
      ...title,
      visitDate: visitedItem ? visitedItem.date : null 
    };
  });

  sortData.sort((a, b) => {
    const dateA = new Date(a.visitDate);
    const dateB = new Date(b.visitDate);

    if (isNaN(dateA.getTime()) && isNaN(dateB.getTime())) {
      return 0;
    } else if (isNaN(dateA.getTime())) {
      return 1;
    } else if (isNaN(dateB.getTime())) {
      return -1;
    } else {
      return dateB.getTime() - dateA.getTime();
    }
  });
  sortData.forEach(suggestion => {
    const isVisited = visitedTitles.some(item => item.title === suggestion.title);

    if (isVisited) 
    {
      const visitedItem = visitedTitles.find(item => item.title === suggestion.title);
      lastVisited = calculateTimeDifference(visitedItem.date);
    }
      
    const suggestionItems = $(
        '<li class="list-group-item border-bottom d-flex btn btn-outline-success" width="200px;">' +
            '<span class="suggestion-title "><i class="fa-solid fa-magnifying-glass fa-xs me-3" style="color: #c4c4c4;"></i>' + suggestion.title + '</span>' + 
            '<span class="text-body-tertiary ms-2" style="scale: 0.7;"><i class="fa-duotone fa-solid fa-eye fa-sm me-1"></i>' + suggestion.popularity + '</span>' + 
        '</li>'
    );

    if(isVisited) {
        suggestionItems.addClass('visited');
    }

  suggestionList.append(suggestionItems);
  });
  

  $('#suggestions').on('click', 'li', function () 
  {
      const title = $(this).find('.suggestion-title').text();
      const currentDate = new Date();
      const gmtPlus8Date = new Date(currentDate.getTime() + 8 * 60 * 60 * 1000);
      const formattedDate = gmtPlus8Date.toISOString().slice(0, 19);

      const visitedItem = {
        title: title,
        date: formattedDate
      };
      visitedTitles.push(visitedItem);
      getByName(title);
      visitedTitles.push(title);
      localStorage.setItem('visitedTitles', JSON.stringify(visitedTitles));
      $('#search-box').val('');
      $('#suggestions').empty();
  });
}

$(document).ready(function() 
{
const debouncedGetSuggestions = debounce(getSuggestions, 300);
  $('#search-box').on('input', debouncedGetSuggestions, function() {
    currentSearchPage = 1;
    getSuggestions();
  });
})