fix(ponyfill/btoa): handle incoming value as binary encoding

.changeset/orange-wombats-brake.md

@@ -0,0 +1,5 @@
+---
+'@whatwg-node/fetch': patch
+---
+
+fix(ponyfill/btoa): handle incoming value as binary encoding

packages/fetch/dist/create-node-ponyfill.js

@@ -61,7 +61,7 @@ module.exports = function createNodePonyfill(opts = {}) {
   ponyfills.btoa = globalThis.btoa
   if (!ponyfills.btoa) {
     ponyfills.btoa = function btoa(data) {
-      return Buffer.from(data).toString('base64');
+      return Buffer.from(data, 'binary').toString('base64');
     };
   }
 

packages/fetch/tests/btoa.spec.ts

@@ -1,4 +1,4 @@
 import { btoa } from '@whatwg-node/fetch';
 it('should work as expected', () => {
-    expect(btoa('Hello, world!')).toBe('SGVsbG8sIHdvcmxkIQ==');
-})
+  expect(btoa('Hello, world!')).toBe('SGVsbG8sIHdvcmxkIQ==');
+});