T9 blogpost - 6

gistfile1.js

Trie.prototype.getSuggestions = function(keyString, suggestionDepth) {  
  // Traverse the tree based on the key digits in keyString, to find the
  // node where relevant words are stored.
  var result = [];
  var node = this;

  for(var i = 0; i < keyString.length; i++) {
    var thisKey = keyString[i];
    if(!node.children.hasOwnProperty(thisKey)) { break; }
    node = node.children[thisKey];
  }

  // Add all the words to the result.
  result = result.concat(node.words.map(function(wordTuple) {
    return wordTuple[0];
  }));
  
  // If suggestionDepth is > 0, the caller is asking for recommendations of 
  // words longer than the number of keys pressed. 
  // We traverse down every possible branch from the point we previously
  // arrived at, adding words to the result as we go and stopping when we
  // reach the specified depth.

  return suggestionDepth > 0 ?
    result.concat(getDeeperSuggestions(node, suggestionDepth)) :
    result;
  // todo: Improvement: If the current string of numbers has no results,
  // even if suggestionDepth is 0, we should dig deeper to find some. 

  function getDeeperSuggestions(root, maxDepth) {
    // ...
  }
};