remove space from username in laravel rule

:

'username' => ['required', 'string', 'max:255', 'unique:users', 'regex:/^\S*$/u'],

Option B:

alpha_dash is a default Laravel validation rule which allows letters, numbers, dashes and underscores and NOT space.

When you implement alpha_dash rule, the field under validation may have alpha-numeric characters, as well as dashes and underscores.

'username' => ['required', 'string', 'max:255', 'unique:users', 'alpha_dash'],

Pay attention that the usual style of validation in Laravel 5.7, 5.8 is a little different with other older versions

Laravel 5.7,5.8:

return Validator::make($data, [
             'A' => ['required', 'string'],
             'B' => ['required', 'string', 'max:255'],
            ]);

Older versions:

return Validator::make($data, [
             'A' => 'required|string',
             'B' => 'required|string|max:255',
            ]);

If you use alpah_dash and enter some value with some spaces at the end or beginning, it trims and passes the validation and works perfectly.