[LeetCode][JavaScript]Binary Tree Paths

 1 /**
 2  * Definition for a binary tree node.
 3  * function TreeNode(val) {
 4  *     this.val = val;
 5  *     this.left = this.right = null;
 6  * }
 7  */
 8 /**
 9  * @param {TreeNode} root
10  * @return {string[]}
11  */
12 var binaryTreePaths = function(root) {
13     var res = [];
14     if(root && root.val !== undefined){
15         getPaths(root, "");
16     }
17     return res;
18 
19     function getPaths(node, path){
20         var isLeaf = true;
21         if(node.left){
22             isLeaf = false;
23             getPaths(node.left, path + "->" + node.val);
24         }
25         if(node.right){
26             isLeaf = false;
27             getPaths(node.right, path + "->" + node.val);
28         }
29         if(isLeaf){
30             var tmp = path + "->" + node.val;
31             res.push(tmp.substring(2, tmp.length));
32         }
33     }
34 };