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 %} 

If we save our template and refresh the browser, we will not see anything displaying yet. The reason is that the offline variable is currently set to false and we are checking to see whether it is true.

Open page.html.twig and edit the offline...