implement key enumerator

README.md

@@ -1,5 +1,5 @@
 # js-redblacktree
-Package provides javascript implementation of red black tree
+Package provides javascript implementation of red black tree. The api of the red black tree is designed so that it matches with the api of the Java counterpart SortedMap api.
 
 
 
@@ -41,5 +41,11 @@ console.log(bst.size()); // display 3
 console.log(bst.containsKey(6)); // display false;
 console.log(bst.get(6)); // display undefined
 
+// print out sorted keys
+
+var keys = bst.keySet();
+for(var i = 1; i < keys.length; ++i) {
+    console.log(keys[i]);
+}
 
 ```

package.json

@@ -1,7 +1,7 @@
 {
   "name": "js-redblacktree",
   "version": "1.0.6",
-  "description": "Package implements various array sorting algorithms",
+  "description": "Package implements left leaning red black balanced search tree for symbol table key-sorted map",
   "author": "Caishun Chen",
   "contributors": [
     "Caishun Chen <cschen1205@gmail.com>"

src/jsrbtree.js

@@ -196,6 +196,23 @@ var jsrbtree = jsrbtree || {};
         return x;
     };
 
+    RedBlackTree.prototype.keySet = function() {
+        var keys = [];
+
+        this._collect(this.root, keys);
+        return keys;
+    };
+
+    RedBlackTree.prototype._collect = function(x, queue) {
+        if (x == null) {
+            return;
+        }  
+
+        this._collect(x.left, queue);
+        queue.push(x.key);
+        this._collect(x.right, queue);
+    };
+
     jss.RedBlackTree = RedBlackTree;
 
 })(jsrbtree);

test/bst-spec.js

@@ -35,6 +35,11 @@ describe("Red Black Tree", function() {
         expect(bst.size()).to.equal(4);
         expect(bst.containsKey(6));
         expect(bst.get(6)).to.equal(5.4);
+
+        var keys = bst.keySet();
+        for(var i = 1; i < keys.length; ++i) {
+            expect(keys[i-1]).to.below(keys[i]);
+        }
     });
 
     it("should delete correctly", function () {