delimitedListOfStringsToTree.js

/* Takes a list ofdelimited strings, where the delimiter is intended to imply
 * a hierarchy ( somewhat like a file system path ) and turns it into
 * a tree-like structure consisting of nodes looking something like
 * { name: "", children: [] }
 * The tree starts at the root node, which is ( no foolin' ) called
 * root.  So the top (root) node is:
 * { name: "root", children: [xxx] }
 */
function listOfDelimitedStringsToTree(lines, delimiter){
  function stringTreeToObjectTree(root){
    var childNodes = []
    for(var name in root){
      childNodes.push({name: name, children: stringTreeToObjectTree(root[name])});
    }
    return childNodes;
  }
  var tree = {};
  // for each of our delimited strings
  for (var i=0;i<lines.length;i++){
    // split things up by delimiter, which gives us
    // one path through the tree
    var tokens = lines[i].split(delimiter);
    // make a reference to the working branch so we can
    // keep our root around (ref'd by tree)
    var workingTree = tree;
    // walk through the tokens building this branch
    // of our tree
    for(var ii=0;ii<tokens.length;ii++){
      var token = tokens[ii];
      workingTree[token] = workingTree[token] || {};
      workingTree = workingTree[token];
    }
  }
  return { name:"root", children: stringTreeToObjectTree(tree) };
}