diff --git a/src/worker-script/browser/index.js b/src/worker-script/browser/index.js
index 06fd336..2e177a8 100644
--- a/src/worker-script/browser/index.js
+++ b/src/worker-script/browser/index.js
@@ -29,4 +29,5 @@ worker.setAdapter({
   gunzip,
   fetch: () => {},
   ...cache,
+  isWebWorker: typeof window === 'undefined' && typeof importScripts === 'function',
 });
diff --git a/src/worker-script/index.js b/src/worker-script/index.js
index 5166ab8..6034cc6 100644
--- a/src/worker-script/index.js
+++ b/src/worker-script/index.js
@@ -99,7 +99,7 @@ const loadLanguage = async ({
         }
 
         if (path !== null) {
-          const resp = await (isWebWorker ? fetch : adapter.fetch)(`${path}/${lang}.traineddata${gzip ? '.gz' : ''}`);
+          const resp = await (isWebWorker || adapter.isWebWorker ? fetch : adapter.fetch)(`${path}/${lang}.traineddata${gzip ? '.gz' : ''}`);
           data = await resp.arrayBuffer();
         } else {
           data = await adapter.readCache(`${langPath}/${lang}.traineddata${gzip ? '.gz' : ''}`);