Book Image

Drupal 10 Module Development - Fourth Edition

By : Daniel Sipos
Book Image

Drupal 10 Module Development - Fourth Edition

By: Daniel Sipos

Overview of this book

Embark on a journey of Drupal module development with the latest edition of this must-have guide written by Daniel Sipos – a Drupal community member! This fourth edition is meticulously revised to cover the latest Drupal 10 enhancements that will help you build custom Drupal modules with an understanding of code deprecations, changing architecture, data modeling, multilingual ecosystem, and so on. You’ll begin with understanding the core components of Drupal 10 architecture, discovering its subsystems and unlocking the secrets of creating your first Drupal module. Further, you'll delve into Drupal logging and mailing systems, creating theme hooks, and rendering a layout. As you progress, you'll work with different types of data storage, custom entities, field types, and work with Database APIs for lower-level database queries. You'll learn to reap the power of JavaScript and ensure that your code works seamlessly on multilingual sites. You'll also learn to create custom views, automate tests for your functionalities, and write secure code for your Drupal apps. By the end of this book, you'll have gained confidence in developing complex modules that can solve even the most complex business problems and might even become a valuable contributor to the Drupal community!
Table of Contents (21 chapters)
3
Chapter 3: Logging and Mailing

The States (Form) system

The last thing we are going to look at in this chapter is the States system of the Form API (not to be confused with the State API we covered in Chapter 6, Data Modeling and Storage). This allows us to define our form elements to behave somewhat dynamically based on the user interaction with the form. It doesn’t use Ajax but relies on JavaScript to handle the manipulations. This is another great example of client-side behavior where we don’t have to write a single line of JavaScript. So, let’s see what this is.

The #states are simple properties we can add to form elements, which have the role of changing them depending on the state of other elements. The best way to understand this is through some examples. Imagine these two form elements:

$form['kids'] = [
  '#type' => 'checkbox',
  '#title' => $this->t('Do you have kids?'),
];
$form['kid_number&apos...