Now, you can probably tell what this does, for the most part!

So, let me break this down!

The “add_filter” function is a built-in, default WordPress filter hook function used to help us Developers to make changes to the default WordPress structure and layout.

Therefore, when we use the following PHP code:

• Add_filter(‘body_class’, ‘cm_logged_in_filter’)

What we are telling WordPress to do is to create a filter that we will call on called “cm_logged_in_filter”. This can be any name you want, but I always use “cm” as a prefix for CreatiqueMedia so I know I was the one that created this customization, plus, they should always be unique so they don’t conflict with something else using a similar name.

So, the “add_filter” function is looking to use the ‘body_class’ and add whatever classes we create! using the following code:

So, I have my custom unique function “cm_logged_in_filter”, then I tell WordPress to use the “$classes” parameter variable that are within the parenthesis. After that, within the function block, I use conditional logic to determine if a user is logged in or not using an “if” statement.

The code that will do this is:

• if( is_user_logged_in() )

Instead of writing my own helper function to determine if a user is logged into WordPress, I can simply just use the already built-in, default helper function called “is_user_logged_in()”. This makes customizations to WordPress so much easier and less cumbersome!

So, the “if” block is:

• if( is_user_logged_in() ) {

$classes[] = ‘logged-in-condition’;

}

After the “if” statement, I use the “$classes” variable again, but this time, I put brackets after it like so:

• $classes[]

What this does is it turns the variable of “$classes” into an array so we can add multiple items to it. For instance, if we just needed or wanted to add one class only, we wouldn’t need to use the array brackets ([]) at all, but since we have two classes we want to add, then we use the array brackets. Of course, you can still use the brackets even with one class, but the point is, that for multiple items, you need the brackets, so most Devs will just stick with the array method, even for one class to avoid human errror down the road.

Okay, to better understand what the “if” statement is doing, let’s imagine a two-way conversation between WordPress and our PHP code: