Drupal 8 Module Development

Altering someone else's emails

Drupal is powerful not only because it allows us to add our own functionality but also because it allows us to alter the existing functionality. An important vector for doing this are the alter hooks. Remember these from Chapter 2, Creating Your Own Module? These are hooks that are used to change the value of an array or object before it is used for whatever purpose it was going to be used for. When it comes to sending mails, we have an alter hook that allows us to change things on the mail definition before it goes out--hook_mail_alter(). For our module, we don't need to implement this hook. However, for the sake of making it complete, let's take a look at how we could use this hook to, for example, change ...