Mastering Drupal 8

Control structures

There will be situations while theming with Twig where we will need to check whether a variable is True or False, or to loop through a variable to output multiple values contained in an array.

Control structures in Twig allow us to account for these types of functions using {%... %} blocks to test for expressions and traverse through variables that contain arrays. Each control structure contains an opening and closing tag, like PHP logic. Let's look at a couple of the most commonly used control structures, starting with the if tag used to test an expression.

Open page.html.twig and add the following:

 {# Conditional logic #} {% set offline = false %} {% if offline == true %} <p>Website is in maintenance mode.</p> {% endif ...