implemented additional route for checking usernames

README.md

@@ -41,10 +41,11 @@ http://localhost:8000/v1/chats
 
 Here's the map of API's HTTP routes:
 
-* `/` — routes related to authentication. 
+* `/` — routes related to authentication.
     * `/signup` **POST** — create new user with `username` and `password`.
     * `/login` **POST** — log user in with `username` and `password`.
     * `/logout` **GET** — log out active user.
+    * `/user-exists?username=john` **GET** — check, whether username is already taken.
 * `/users` — routes related to users.
     * `/users` **GET** — retrieve data about all users.
     * `/users/me` **GET** — retrieve my user's data.

controllers/auth.js

@@ -102,8 +102,31 @@ function logout() {
   });
 }
 
+function userExists(username) {
+  if (!username) {
+    return Promise.reject({
+      success: false,
+      message: 'Username is not provided',
+    });
+  }
+  return User.findOne({ username })
+    .exec()
+    .then((user) => {
+      if (user) {
+        return Promise.reject({
+          success: false,
+          message: 'Username is already taken',
+        });
+      }
+      return Promise.resolve({
+        success: true,
+      });
+    });
+}
+
 module.exports = {
   signUp,
   login,
   logout,
+  userExists,
 };

routes/auth.js

@@ -67,4 +67,22 @@ authRouter.get('/logout', (req, res, next) => {
     });
 });
 
+authRouter.get('/user-exists', (req, res, next) => {
+  const { username } = req.query;
+  authConroller
+    .userExists(username)
+    .then((result) => {
+      res.json({
+        success: result.success,
+      });
+    })
+    .catch((error) => {
+      res.json({
+        success: false,
+        message: error.message,
+      });
+      next(error);
+    });
+});
+
 module.exports = authRouter;