refactor: reuse oauthVerify function

server/src/auth/githubStrategy.js

@@ -1,41 +1,10 @@
 import GitHubStrategy from 'passport-github2'
 
 import config from '../config.js'
-import User from '../models/user.js'
+import oauthVerify from './oauthVerify.js'
 
 function verify(accessToken, refreshToken, profile, cb) {
-  process.nextTick(async () => {
-    const email = profile.emails[0]?.value
-    if (!email) {
-      cb(new Error('No email found'))
-      return
-    }
-
-    let user = await User.findOne({ 'github.id': profile.id })
-    if (!user) {
-      user = await User.findOne({ email })
-      const github = {
-        id: profile.id,
-        displayName: profile.displayName,
-      }
-      if (!user) {
-        const newUser = {
-          email,
-          github,
-        }
-        cb(null, { newUser })
-        return
-      }
-      if (user.github?.id) {
-        cb(new Error('Email already used and binded to another account'))
-        return
-      }
-      user.github = github
-      await user.save()
-    }
-
-    cb(null, user)
-  })
+  oauthVerify('github', profile, { 'github.id': profile.id }, cb)
 }
 
 const enabled = config.github.clientID && config.github.clientSecret