Created shell for the AVL tree

index.js

@@ -0,0 +1,2 @@
+module.exports.BinarySearchTree = require('./lib/bst');
+module.exports.AVLTree = require('./lib/avltree');

lib/avltree.js

@@ -0,0 +1,40 @@
+/**
+ * Self-balancing binary search tree using the AVL implementation
+ */
+var BinarySearchTree = require('./bst')
+  , customUtils = require('./customUtils')
+  , util = require('util')
+  ;
+
+/**
+ * Constructor
+ * @param {Object} options Optional
+ * @param {Boolean}  options.unique Whether to enforce a 'unique' constraint on the key or not
+ * @param {Key}      options.key Initialize this BST's key with key
+ * @param {Value}    options.value Initialize this BST's data with [value]
+ * @param {Function} options.compareKeys Initialize this BST's compareKeys
+ */
+function AVLTree (options) {
+  options = options || {};
+
+  this.left = null;
+  this.right = null;
+  this.parent = options.parent !== undefined ? options.parent : null;
+  this.key = options.key !== undefined ? options.key : null;
+  this.data = options.value ? [options.value] : [];
+  this.unique = options.unique || false;
+
+  this.compareKeys = options.compareKeys || customUtils.defaultCompareKeysFunction;
+  this.checkValueEquality = options.checkValueEquality || customUtils.defaultCheckValueEquality;
+}
+
+
+/**
+ * Inherit basic functions from the basic binary search tree
+ */
+util.inherits(AVLTree, BinarySearchTree);
+
+
+
+// Interface
+module.exports = AVLTree;

lib/bst.js

@@ -1,25 +1,7 @@
 /**
  * Simple binary search tree
  */
-
-/*
- * Default compareKeys function will work for numbers, strings and dates
- */
-function defaultCompareKeysFunction (a, b) {
-  if (a < b) { return -1; }
-  if (a > b) { return 1; }
-  if (a === b) { return 0; }
-
-  throw { message: "Couldn't compare elements", a: a, b: b };
-}
-
-
-/**
- * Check whether two values are equal (used in non-unique deletion)
- */
-function defaultCheckValueEquality (a, b) {
-  return a === b;
-}
+var customUtils = require('./customUtils');
 
 
 /**
@@ -40,8 +22,8 @@ function BinarySearchTree (options) {
   this.data = options.value ? [options.value] : [];
   this.unique = options.unique || false;
 
-  this.compareKeys = options.compareKeys || defaultCompareKeysFunction;
-  this.checkValueEquality = options.checkValueEquality || defaultCheckValueEquality;
+  this.compareKeys = options.compareKeys || customUtils.defaultCompareKeysFunction;
+  this.checkValueEquality = options.checkValueEquality || customUtils.defaultCheckValueEquality;
 }
 
 

lib/customUtils.js

@@ -14,3 +14,25 @@ function getRandomArray (n) {
   return res;
 };
 module.exports.getRandomArray = getRandomArray;
+
+
+/*
+ * Default compareKeys function will work for numbers, strings and dates
+ */
+function defaultCompareKeysFunction (a, b) {
+  if (a < b) { return -1; }
+  if (a > b) { return 1; }
+  if (a === b) { return 0; }
+
+  throw { message: "Couldn't compare elements", a: a, b: b };
+}
+module.exports.defaultCompareKeysFunction = defaultCompareKeysFunction;
+
+
+/**
+ * Check whether two values are equal (used in non-unique deletion)
+ */
+function defaultCheckValueEquality (a, b) {
+  return a === b;
+}
+module.exports.defaultCheckValueEquality = defaultCheckValueEquality;