Revert "goes back to accessToken.token"

This reverts commit ebe9a50.

src/pages/api/callback.ts

@@ -0,0 +1,31 @@
+import type { NextApiRequest, NextApiResponse } from 'next';
+import { renderBody, createClient } from '@/lib/oauth2';
+
+export default async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse
+) {
+  const code = req.query.code;
+  const { host } = req.headers;
+
+  const oauthClient = createClient();
+
+  try {
+    const accessToken = await oauthClient.getToken({
+      code,
+      redirect_uri: `https://${host}/api/callback`,
+      scope: `repo,user`,
+    });
+
+    const { token } = oauthClient.createToken(accessToken);
+
+    res.status(200).send(
+      renderBody('success', {
+        token: token.access_token,
+        provider: 'github',
+      })
+    );
+  } catch (e) {
+    res.status(200).send(renderBody('error', e));
+  }
+}