Trie.js

// Defines the node object
var Node = function(options) {
  var options = options || {};
  this.value = options.value;
  this.parent = options.parent;
  this.children = options.children || {};
  this.stop = options.stop;
};

var Trie = function() {
  this.head = new Node();

  // Inserts string into the Trie.
  this.insert = function(string) {
    var currentNode = this.head;
    var word = string.split('');
    for(var i = 0; i < word.length; i++){
      var letter = word[i];
      if(currentNode.children[letter] === undefined){
        var options = {parent: currentNode, value: word[i], children: {}, stop: false};
        currentNode.children[word[i]] = new Node(options);
      }
      currentNode = currentNode.children[word[i]];
    }
    currentNode.stop = true;
    console.log(this.head);
  };

  // Recursive function. Helper function for the insert function.
  this._insert = function() {
  };

  // Returns true if string is in the trie. Returns false otherwise.
  this.includes = function(string) {
    if(!string){
      return false;
    }
    currentNode = this.head
    for(var i=0; i < string.length; i++){
      if(currentNode.children[string[i]] === undefined){
        return false;
      }
      else {
        currentNode = currentNode.children[string[i]];
      }
    }

    if(currentNode.stop === true){
      return true;
    }
    else {
      return false;
    }
  };

  // Recursive function. Returns true if string is in the trie. Returns false
  // otherwise.
  this._includes = function() {

  };

  // Search for all strings that have 'prefix' as the prefix.
  //
  // Returns Array of Strings.
  this.search = function(prefix) {

  };

  // Recursive function. Helper function for the search function.
  this._search = function() {

  };

  // Find the node that correspond to the last character in the string.
  //
  // Returns Node.
  this.findLastNode = function(string) {

  };

  // Recursive function. Helper function for the findLastNode function.
  this._findLastNode = function() {

  };

  // Given a node, return all the strings that are part of this node.
  //
  // Returns Array of Strings.
  this.iterate = function(node) {
    if (node === undefined){
      return [];
    }

    var result = [];
    var actualResult = [];
    var str = node.value;
    result.push(this._iterate(str, node));
    actualResult = actualResult.concat.apply(actualResult, result);
    return actualResult;
  };

  // Recursive helper function for .iterate
  this._iterate = function(str, node) {
    var result = [];
    var children = node.children;
    var keys = Object.keys(children);
    if(keys.length === 0){
      result.push(str);
      return result;
    }

    for(var i = 0; i < keys.length; i++){
      var local = str + children[keys[i]].value;
      if (children[keys[i]].stop){
        result.push(local);
      }
      else {
        result.push( this._iterate(local, children[keys[i]]) );
      }
    }
  };

  // You may find this function useful for implementing iterate().
  //
  // Returns true if object is empty. False otherwise.
  this.isEmpty = function (object) {
    for(var i in object) {
      return false;
    }
    return true;
  }
};