trie.js

var fs = require('fs'); // import for index_emails

function Trie() {
  this.head = {};
};

// want to make sure we have valid words
Trie.prototype.validate = function(word) { 
  if ((word === undefined) || (word === null) || (typeof word !== "string")) throw "invalid input";
}

// basic gist is to check if a node exists in a given sequence (prefix) and if it doesn't create a new one
Trie.prototype.add = function(word) {
  this.validate(word)
  var node = this.head;

  for (var i = 0; i < word.length; i++) { 
    if(!(word[i] in node)) {
      node[word[i]] = {};
    }
    node = node[word[i]]
  };

  node.isEnd = true
};

// follow the trie from node to node to see if it has it
Trie.prototype.contains = function(word) {
  this.validate(word)
  var node = this.head;

  for (var i = 0; i < word.length; i++) { 
    if(!(word[i] in node)) {
      return false;
    }
    node = node[word[i]]
  };
  return node.isEnd === true;
};


// get a list of file paths (not necessarily in a child dir), add them to the trie
// doing this async would be preferable as it's currently blockinig
Trie.prototype.index_emails = function(path) {
  var self = this;
  fs.readdirSync(path).forEach(function(dirname) {
    self.add(dirname)
  })

  return self;
}

// TODO
Trie.prototype.test = function(word, trie) {

}

export default Trie