--- a/devtools/client/shared/file-watcher.js
+++ b/devtools/client/shared/file-watcher.js
@@ -10,17 +10,17 @@ function watchFiles(path, onFileChanged)
     "resource://devtools/client/shared/file-watcher-worker.js"
   );
 
   watchWorker.onmessage = event => {
     // We need to turn a local path back into a resource URI (or
     // chrome). This means that this system will only work when built
     // files are symlinked, so that these URIs actually read from
     // local sources. There might be a better way to do this.
-    const { newPath } = event.data;
+    const { path: newPath } = event.data;
     onFileChanged(newPath);
   };
 
   watchWorker.postMessage({
     path,
     fileRegex: /\.(js|css|svg|png)$/
   });
   return watchWorker;