Trie Implementation in Javascript

trie.js

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

  // for finding out word from leaf to root of trie
  findWord() {
    let node = this;
    let word = [];

    while(node.parent != null) {
      word.unshift(node.key);
      node = node.parent;
    }

    return word.join('');
  }

}


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

  // to insert the word letter by letter in the trie
  insert(word) {

    let node = this.root;
   
    for(let i=0; i<word.length; i++) {
    
      if(!node.children[word[i]]) {
        node.children[word[i]] = new TrieNode(word[i]);
        node.children[word[i]].parent = node;
      } 

      node = node.children[word[i]];

      if(i == word.length - 1)
        node.end = true;

    }

  } 

  // check to see if the trie contains the word or not
  containsWord(word) {

    let node = this.root;

    for(let i=0; i<word.length; i++) {

      if(!node.children[word[i]]) return false;

      node = node.children[word[i]];

    }

    return node.end;

  }

  // gives the autocomplete suggestion for given prefix in form of an array
  autocomplete(prefix) {

    let node = this.root;
    let output = [];

    for(let i=0; i<prefix.length; i++)  {

      if(!node.children[prefix[i]]) return output;

      node = node.children[prefix[i]];

    }

    this.findAllWords(node, output);

    return output;

  }

  // recursively find all the words by exploring all of its children nodes
  findAllWords(node, output) {

    if(node.end) {
      output.push(node.findWord());
    } else {
      for(var i in node.children) {
        this.findAllWords(node.children[i], output)
      }
    }
  }

  // check to see there is word(s) starting with the given prefix
  startsWith(prefix) {

    let node = this.root;

    for(let i=0; i<prefix.length; i++) {

      if(!node.children[prefix[i]]) return false;
      node = node.children[prefix[i]];

    }

    return true;

  } 



  print() {
    console.log(this.root);
  }


}



let t = new Trie();

t.insert('apple');
t.insert('ant');
t.insert('andromedia')

console.log(t.containsWord('ant'));  // output: true
console.log(t.containsWord('banana')); // output: false

console.log(t.autocomplete('an')); // output: ['ant', 'andromedia']
console.log(t.autocomplete('b')); // output:  []

console.log(t.startsWith('and')); // output: true

t.print();