BE Bonny Elangbam.
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snippet 1 min read PHP 8.0+ WP 6.4+

A safer WordPress hook for body classes

Add a useful context class to the body element without coupling your theme to a page template.

#wordpress #php #snippet

WordPress gives us a clean filter for adding semantic context to the <body> element. This tiny hook makes CSS and client-side behavior easier to target while keeping the logic in one place.

The snippet

functions.php
add_filter('body_class', function (array $classes): array {
    if (is_singular('product')) {
        $classes[] = 'is-product-single';
    }


    return $classes;
});

The callback receives the classes WordPress has already assembled, so we only append the context we need and return the complete array.

Why this holds up

  • It uses the public body_class extension point.
  • The type declaration makes the expected input and output obvious.
  • is_singular() keeps the class scoped to the relevant content type.

That last point matters: a hook should add context, not make every page carry assumptions about a single template.