1 files changed, 25 insertions, 0 deletions
diff --git a/tools/eslint/lib/rules/no-undefined.js b/tools/eslint/lib/rules/no-undefined.js
new file mode 100644
index 0000000000..4d96eb3e92
--- /dev/null
+++ b/tools/eslint/lib/rules/no-undefined.js
@@ -0,0 +1,25 @@
+/**
+ * @fileoverview Rule to flag references to the undefined variable.
+ * @author Michael Ficarra
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = function(context) {
+
+    return {
+
+        "Identifier": function(node) {
+            if (node.name === "undefined") {
+                var parent = context.getAncestors().pop();
+                if (!parent || parent.type !== "MemberExpression" || node !== parent.property || parent.computed) {
+                    context.report(node, "Unexpected use of undefined.");
+                }
+            }
+        }
+    };
+
+};