1 files changed, 73 insertions, 0 deletions
diff --git a/tools/eslint/lib/rules/consistent-return.js b/tools/eslint/lib/rules/consistent-return.js
new file mode 100644
index 0000000000..38adba7f31
--- /dev/null
+++ b/tools/eslint/lib/rules/consistent-return.js
@@ -0,0 +1,73 @@
+/**
+ * @fileoverview Rule to flag consistent return values
+ * @author Nicholas C. Zakas
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = function(context) {
+
+    var functions = [];
+
+    //--------------------------------------------------------------------------
+    // Helpers
+    //--------------------------------------------------------------------------
+
+    /**
+     * Marks entrance into a function by pushing a new object onto the functions
+     * stack.
+     * @returns {void}
+     * @private
+     */
+    function enterFunction() {
+        functions.push({});
+    }
+
+    /**
+     * Marks exit of a function by popping off the functions stack.
+     * @returns {void}
+     * @private
+     */
+    function exitFunction() {
+        functions.pop();
+    }
+
+
+    //--------------------------------------------------------------------------
+    // Public
+    //--------------------------------------------------------------------------
+
+    return {
+
+        "Program": enterFunction,
+        "FunctionDeclaration": enterFunction,
+        "FunctionExpression": enterFunction,
+        "ArrowFunctionExpression": enterFunction,
+
+        "Program:exit": exitFunction,
+        "FunctionDeclaration:exit": exitFunction,
+        "FunctionExpression:exit": exitFunction,
+        "ArrowFunctionExpression:exit": exitFunction,
+
+        "ReturnStatement": function(node) {
+
+            var returnInfo = functions[functions.length - 1],
+                returnTypeDefined = "type" in returnInfo;
+
+            if (returnTypeDefined) {
+
+                if (returnInfo.type !== !!node.argument) {
+                    context.report(node, "Expected " + (returnInfo.type ? "a" : "no") + " return value.");
+                }
+
+            } else {
+                returnInfo.type = !!node.argument;
+            }
+
+        }
+    };
+
+};