Add possibility to mock undefined, implicit globals

Fixes #35

1 files changed, 14 insertions, 2 deletions

diff --git a/lib/__set__.js b/lib/__set__.js
index 851a340..bdb5042 100644
--- a/lib/__set__.js
+++ b/lib/__set__.js
@@ -25,7 +25,13 @@ function __set__() {
             if (arguments.env.hasOwnProperty(arguments.varName)) {
                 arguments.varValue = arguments.env[arguments.varName];
                 arguments.src += arguments.varName + " = arguments.env[" + JSON.stringify(arguments.varName) + "]; ";
-                arguments.revertArgs[0][arguments.varName] = eval(arguments.varName);
+                try {
+                    // Allow tests to mock implicit globals
+                    // @see https://github.com/jhnns/rewire/issues/35
+                    arguments.revertArgs[0][arguments.varName] = eval(arguments.varName);
+                } catch (err) {
+                    arguments.revertArgs[0][arguments.varName] = undefined;
+                }
             }
         }
     } else if (typeof arguments.varName === "string" && arguments.length === 2) {
@@ -33,7 +39,13 @@ function __set__() {
             throw new TypeError("__set__ expects a non-empty string as a variable name");
         }
         arguments.src = arguments.varName + " = arguments.varValue;";
-        arguments.revertArgs = [arguments.varName, eval(arguments.varName)];
+        try {
+            // Allow tests to mock implicit globals
+            // @see https://github.com/jhnns/rewire/issues/35
+            arguments.revertArgs = [arguments.varName, eval(arguments.varName)];
+        } catch (err) {
+            arguments.revertArgs = [arguments.varName, undefined];
+        }
     } else {
         throw new TypeError("__set__ expects an environment object or a non-empty string as a variable name");
     }