Undefined Variable: token in Laravel Login Postman test - laravel

Question

I wrote an API in Laravel 5.8 for User Login and Register.
I use JWTAuth in Laravel 5.8. When I tested the Login on Postman, it generated an error, undefined variable: token. I tried to write the API for register, when I tested it, it worked perfectly. Based on what I saw online, I tried adding \Illuminate\View\Middleware\ShareErrorsFromSession::class, to the kernel but still the same error.
LoginController
public function login(Request $request)
{
$credentials = $request->json()->all();
try
{
if(! $token == JWTAuth::attempt($credentials))
{
return response()->json(['error' => 'invalid_credentials'], 400);
}
}
catch(JWTException $e)
{
return response()->json(['error' => 'could_not_create_token'], 500);
}
return response()->json(compact('token'));
}
public function register(Request $request)
{
$validator = Validator::make($request->json()->all() , [
'name' => 'required|string|max:255',
'email' => 'required|string|email|max:255|unique:users',
'password' => 'required|string|min:6',
'username' => 'required|string|max:255',
]);
if($validator->fails()){
return response()->json($validator->errors()->toJson(), 400);
}
$user = User::create([
'name' => $request->json()->get('name'),
'email' => $request->json()->get('email'),
'password' => Hash::make($request->json()->get('password')),
'username' => $request->json()->get('username'),
]);
$token = JWTAuth::fromUser($user);
return response()->json(compact('user', 'token'), 201);
}
api.php
Route::middleware('auth:api')->get('/user', function (Request $request) {
return $request->user();
});
Route::post('register', 'UserController#register');
Route::post('login', 'UserController#login');
Route::get('profile', 'UserController#getAuthenticatedUser');
I expected success, but it gave error:
ErrorException: Undefined variable: token in file C:\xampp\htdocs\laravelapi\app\Http\Controllers\UserController.php on line 52
This is my line 52:
if(! $token == JWTAuth::attempt($credentials))

Answer 1

define $token before line 52
$token = null;

Answer 2

You should use assignment operator and not equal ==:
$token = JWTAuth::attempt($credentials))
Also in the login function you should generate a token from user to return
public function login(Request $request)
{
$credentials = $request->json()->all();
try
{
if(! $token = JWTAuth::attempt($credentials))
{
return response()->json(['error' => 'invalid_credentials'], 400);
} else {
// Generate token from user
$token = JWTAuth::attempt($credentials);
return response()->json(compact('token'));
}
}
catch(JWTException $e)
{
return response()->json(['error' => 'could_not_create_token'], 500);
}
}