Breadth-First Traversal of a Binary Tree.js

gistfile1.js

/**
 * Breadth-First Traversal of a Binary Tree in JS
 * by Adrian Statescu <adrian@thinkphp.ro>
 * MIT Style License
 */

       function Node(info){

           this.info = info
           this.left = null;
           this.right = null;
           this.level = null; 
       }

       Node.prototype.toString = function() {
           return this.info;
       }  

       function BFT(node) {

            node.level = 1;
 
            var queue = [node];

            var output = [];

            var current_level = node.level;
 
                while(queue.length > 0) {

                      current_node = queue.shift(); 

                      if(current_node.level > current_level) {

                             current_level++;
                             output.push("\n");
                      }  

                      output.push(current_node + " ");

                      if(current_node.left) {
                           current_node.left.level = current_level + 1; 
                           queue.push(current_node.left); 
                      }  

                      if(current_node.right) {
                           current_node.right.level = current_level + 1; 
                           queue.push(current_node.right); 
                      }  
                      
                }
 
             return output.join("") 
       }

/*
       9
    1      3
  2   4  6   8
a   b   c 
 */

       var root = new Node(9);
           root.left = new Node(8);    
           root.right = new Node(7);

           root.left.left = new Node(2);
           root.left.right = new Node(4);

           root.right.left = new Node(6);
           root.right.right = new Node(8);

           root.left.left.left = new Node('a');
           root.left.left.right = new Node('b');

           root.left.right.right = new Node('c');

           alert(BFT(root))