diff --git a/src/index.js b/src/index.js
index <HASH>..<HASH> 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,11 +1,13 @@
 export default function (opts = {}) {
   const isJsonFile = opts.filter || /\.json$/;
   return (override, transform) => {
-    transform("readSource", function (source, [module]) {
+    transform("readSource", function (module) {
       if (isJsonFile.test(module.path)) {
-        source = `module.exports = ${source};`;
+        module = Object.assign({}, module, {
+          rawSource: `module.exports = ${module.rawSource};`
+        });
       }
-      return source;
+      return module;
     });
   };
 }
Bring `readSource` transform up-to-date with Interlock API.