janetlee · December 15, 2017 17:19 · Dec 15, 2017
diff --git a/deepEquality.js b/deepEquality.js
@@ -0,0 +1,33 @@
+/**
+  * Write a function that, given two objects, returns whether or not the two
+  * are deeply equivalent--meaning the structure of the two objects is the
+  * same, and so is the structure of each of their corresponding descendants.
+  *
+  * Examples:
+  *
+  * deepEquals({a:1, b: {c:3}},{a:1, b: {c:3}}); // true
+  * deepEquals({a:1, b: {c:5}},{a:1, b: {c:6}}); // false
+  *
+  * don't worry about handling cyclical object structures.
+  *
+  
+  NOTE: if your interviewee immediately jumps to a JSON.stringify-based solution, acknowledge that it is a 
+  naive & valid implementation but add it as a constraint to NOT use it for their solution. 
+  */
+
+// Solution
+
+var deepEquals = function(apple, orange) {
+
+  if (apple === orange) { return true; }
+  if (apple && !orange || !apple && orange) { return false; }
+  if (!(apple instanceof Object) || !(orange instanceof Object)) { return false; }
+  var appleKeys = Object.keys(apple);
+  var orangeKeys = Object.keys(orange);
+  if (appleKeys.length !== orangeKeys.length) { return false; }
+  if (appleKeys.length === 0) { return true; } // two empty objects are equal
+  for (var i = 0; i < appleKeys.length; i++) {
+    if (!deepEquals(apple[appleKeys[i]], orange[appleKeys[i]])) { return false; }
+  }
+  return true;
+};