refacotr: simplify default callbacks lib file

src/server/index.js

@@ -5,7 +5,7 @@ import cookie from './lib/cookie'
 import callbackUrlHandler from './lib/callback-url-handler'
 import parseProviders from './lib/providers'
 import events from './lib/events'
-import callbacks from './lib/callbacks'
+import * as defaultCallbacks from './lib/defaultCallbacks'
 import providers from './routes/providers'
 import signin from './routes/signin'
 import signout from './routes/signout'
@@ -21,7 +21,7 @@ if (!process.env.NEXTAUTH_URL) {
   logger.warn('NEXTAUTH_URL', 'NEXTAUTH_URL environment variable not set')
 }
 
-async function NextAuth (req, res, userSuppliedOptions) {
+async function NextAuthHandler (req, res, userSuppliedOptions) {
   // To the best of my knowledge, we need to return a promise here
   // to avoid early termination of calls to the serverless function
   // (and then return that promise when we are done) - eslint
@@ -139,7 +139,7 @@ async function NextAuth (req, res, userSuppliedOptions) {
 
     // Callback functions
     const callbacksOptions = {
-      ...callbacks,
+      ...defaultCallbacks,
       ...userSuppliedOptions.callbacks
     }
 
@@ -314,10 +314,10 @@ async function NextAuth (req, res, userSuppliedOptions) {
   })
 }
 
-export default async (...args) => {
+export default async function NextAuth (...args) {
   if (args.length === 1) {
-    return (req, res) => NextAuth(req, res, args[0])
+    return (req, res) => NextAuthHandler(req, res, args[0])
   }
 
-  return NextAuth(...args)
+  return NextAuthHandler(...args)
 }

src/server/lib/callbacks.js → src/server/lib/defaultCallbacks.js

@@ -9,19 +9,14 @@
  * requests to sign in and again when they activate the link in the sign in
  * email.
  *
- * @param  {object} profile  User profile (e.g. user id, name, email)
- * @param  {object} account  Account used to sign in (e.g. OAuth account)
- * @param  {object} metadata Provider specific metadata (e.g. OAuth Profile)
- * @return {boolean|object}  Return `true` (or a modified JWT) to allow sign in
- *                           Return `false` to deny access
+ * @param  {object} profile          User profile (e.g. user id, name, email)
+ * @param  {object} account          Account used to sign in (e.g. OAuth account)
+ * @param  {object} metadata         Provider specific metadata (e.g. OAuth Profile)
+ * @return {Promise<boolean|never>}  Return `true` (or a modified JWT) to allow sign in
+ *                                   Return `false` to deny access
  */
-const signIn = async (profile, account, metadata) => {
-  const isAllowedToSignIn = true
-  if (isAllowedToSignIn) {
-    return Promise.resolve(true)
-  } else {
-    return Promise.resolve(false)
-  }
+export async function signIn () {
+  return true
 }
 
 /**
@@ -31,12 +26,13 @@ const signIn = async (profile, account, metadata) => {
  *
  * @param  {string} url      URL provided as callback URL by the client
  * @param  {string} baseUrl  Default base URL of site (can be used as fallback)
- * @return {string}          URL the client will be redirect to
+ * @return {Promise<string>} URL the client will be redirect to
  */
-const redirect = async (url, baseUrl) => {
-  return url.startsWith(baseUrl)
-    ? Promise.resolve(url)
-    : Promise.resolve(baseUrl)
+export async function redirect (url, baseUrl) {
+  if (url.startsWith(baseUrl)) {
+    return url
+  }
+  return baseUrl
 }
 
 /**
@@ -45,31 +41,24 @@ const redirect = async (url, baseUrl) => {
  *
  * @param  {object} session  Session object
  * @param  {object} token    JSON Web Token (if enabled)
- * @return {object}          Session that will be returned to the client
+ * @return {Promise<object>} Session that will be returned to the client
  */
-const session = async (session, token) => {
-  return Promise.resolve(session)
+export async function session (session) {
+  return session
 }
 
 /**
  * This callback is called whenever a JSON Web Token is created / updated.
  * e.g. On sign in, `getSession()`, `useSession()`, `/api/auth/session` (etc)
  *
- * On initial sign in, the raw oAuthProfile is passed if the user is signing in
+ * On initial sign in, the raw OAuthProfile is passed if the user is signing in
  * with an OAuth provider. It is not avalible on subsequent calls. You can
  * take advantage of this to persist additional data you need to in the JWT.
  *
  * @param  {object} token         Decrypted JSON Web Token
  * @param  {object} oAuthProfile  OAuth profile - only available on sign in
- * @return {object}               JSON Web Token that will be saved
+ * @return {Promise<object>}      JSON Web Token that will be saved
  */
-const jwt = async (token, oAuthProfile) => {
-  return Promise.resolve(token)
-}
-
-export default {
-  signIn,
-  redirect,
-  session,
-  jwt
+export async function jwt (token) {
+  return token
 }