diff --git a/um_wasm/src/exports/ncm.rs b/um_wasm/src/exports/ncm.rs
index 031f577..4e41773 100644
--- a/um_wasm/src/exports/ncm.rs
+++ b/um_wasm/src/exports/ncm.rs
@@ -3,7 +3,7 @@ use umc_ncm::NetEaseCryptoError;
 use wasm_bindgen::prelude::wasm_bindgen;
 use wasm_bindgen::JsError;
 
-/// QMC Footer.
+/// NCMFile
 #[wasm_bindgen(js_name=NCMFile)]
 pub struct JsNCMFile {
     ncm: Option<NCMFile>,
@@ -11,6 +11,12 @@ pub struct JsNCMFile {
 
 #[wasm_bindgen(js_class=NCMFile)]
 impl JsNCMFile {
+    /// Create a NCMFile instance
+    #[wasm_bindgen(constructor)]
+    pub fn new() -> Result<JsNCMFile, JsError> {
+        Ok(JsNCMFile { ncm: None })
+    }
+
     /// Open NCM file.
     /// If everything is ok, return `0`.
     ///
diff --git a/um_wasm_loader/build.js b/um_wasm_loader/build.js
index d689266..62e6e4d 100644
--- a/um_wasm_loader/build.js
+++ b/um_wasm_loader/build.js
@@ -92,6 +92,9 @@ async function main() {
   // Ask rollup to build bundles.
   await run(['pnpm', 'build:bundle']);
   await run(['pnpm', 'exec', 'prettier', '--ignore-path', '', '-w', 'dist/loader.d.ts']);
+  await replaceFileByRegex(path.join(wasmDistDir, 'loader.mjs'), [
+    ['fetch(filepath)', 'fetch(new URL(filepath, import.meta.url))'],
+  ]);
 }
 
 main()