Custom login create in drupal 8.

We are trying to clear the code of custom login with authentication. here we have the code.

 // Authentication of username and password..
$uid = \Drupal::service('user.auth')->authenticate($username,$password);
// Get the user id by database and load..
$user = \Drupal\user\Entity\User::load($uid);
// finally pass the user detail array in user login function..
 user_login_finalize($user);

Example:
 Like we have username and password by POST method and fields are.
<input id="login-username" type="text" class="form-control" name="name" value="" placeholder="username">
<input id="login-password" type="password" class="form-control" name="pass" placeholder="password">

so for got these credentials in function the code is.
$username = \Drupal::request()->request->get('name'); // form username
$password = \Drupal::request()->request->get('pass'); // form password

And the final code for login..

 $uid = \Drupal::service('user.auth')->authenticate($username,$password);
 $user = \Drupal\user\Entity\User::load($uid);
 user_login_finalize($user);
 
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