如何显示Flash消息Laravel 5.7

I want a show a flash message in my login page user register and
redirect back with success message to login page how to show flash message in a login page

this is the function RegisterController.php

public function register(Request $request)
{
    $this->validator($request->all())->validate();

    event(new Registered($user = $this->create($request->all())));

    return redirect($this->redirectPath())->withMessage('message', 'my msg');        

}

login.blade.php

 @if (session('message'))
  <div class="alert alert-success" role="alert">
   {{ session('message') }}
    </div>
@endif

When you use withMessage('message', 'my msg') you already gave the key to your message. So either use just withMessage('my msg') or ->with('message', 'my msg').

And noticing the other answers using the flash separately, but with already uses flash session.

Add Session::flash('message', 'Your message!'); to your controller.

Change in your controller like this:

return redirect($this->redirectPath())->with('message', ['my msg']); 

You can try bellow code:

In controller:

use Session;
Session::flash('success','Success Message.');
Session::flash('danger','Error Message.');
Session::flash('warning','Warning Message.');
Session::flash('info','Info Message.');

In blade file:

@foreach (['danger', 'warning', 'success', 'info'] as $msg)
    @if(Session::has('alert-' . $msg))
        <p class="success text-{{ $msg }}">{{ Session::get('alert-' . $msg) }}</p>
    @endif
@endforeach