Trie Implementation in JavaScript . It also includes Auto-complete.

Trie.js

class TrieNode {
  constructor() {
    this.children = {};
    this.end = false;
  }
}

class Trie {
  constructor() {
    this.root = new TrieNode();
  }

  insert = (word) => {
    let node = this.root;
    for (let i = 0; i < word.length; i++) {
      const char = word[i];
      if (!node.children[char]) {
        node.children[char] = new TrieNode();
      }
      node = node.children[char];
    }
    node.end = true;
  };

  /**
   * Auto-complete feature.
   * @tutorial  O(P) where P is the prefix length
   */
  search = (word) => {
    let node = this.root;
    for (const char of word) {
      if (!node.children[char]) return [];
      node = node.children[char];
    }
    return this.findWords(node, word);
  };

  findWords = (node, prefix) => {
    const suggestions = [];
    if (node.end) suggestions.push(prefix);
    for (const char in node.children) {
      suggestions.push(...this.findWords(node.children[char], prefix + char));
    }
    return suggestions;
  };

  startsWith = (prefix) => {
    let node = this.root;
    for (let i = 0; i < prefix.length; i++) {
      const char = prefix[i];
      if (!node.children[char]) return false;
      node = node.children[char];
    }
    return true;
  };

  delete = (word) => {
    this.#deleteRecursively(this.root, word, 0);
  };

  #deleteRecursively = (node, word, index) => {
    const hasDeleted = Object.keys(node.children).length === 0;
    if (index === word.length) {
      if (node.end) node.end = false;
      return hasDeleted;
    }
    const char = word[index];
    if (!node.children[char]) return false; //Word doesnt exist

    const shouldDeleteChild = this.#deleteRecursively(
      node.children[char],
      word,
      index + 1
    );

    if (shouldDeleteChild) {
      delete node.children[char];
      return hasDeleted;
    }
    return false;
  };
}

const trie = new Trie();
trie.insert("apple");
trie.insert("appetizer");
trie.insert("banana");
trie.insert("bat");
trie.insert("ball");
trie.delete("banana");
console.log(trie.startsWith("ba")); //true
console.log(trie.search("ba")); //[ 'bat', 'ball' ]