I have different headers for different categories within Woocommerce on my website.
I am checking the product category string against an array with the in_array function. Before using the get_template_part function to output the different header to the page.
This code was working fine and has only recently, randomly. Started displaying the PHP error message 'Warning: in_array() expects parameter 2 to be array, null given in'.
// Gets the product categories to loop over and out put based on scenario below.
$terms = wp_get_post_terms( $post->ID, 'product_cat' );
foreach ( $terms as $term ) $categories[] = $term->slug;
if ( is_front_page() ) {
get_template_part( '/includes/header/header', 'front' );
} elseif ( in_array( 'courses', $categories ) ) {
get_template_part( '/includes/woocommerce/headers/woocommerce', 'single' );
} elseif ( in_array( 'services', $categories ) ) {
get_template_part( '/includes/woocommerce/headers/woocommerce', 'services' );
} elseif (is_product_category() || is_shop()) {
get_template_part( '/includes/woocommerce/headers/woocommerce', 'archive' );
}
else {
get_template_part( '/includes/header/header', 'with-menus' );
}
You need to initialize $categories as empty array before foreach runs:
$terms = wp_get_post_terms( $post->ID, 'product_cat' );
$categories = array();
foreach ( $terms as $term ) $categories[] = $term->slug;
[...]
If $terms is empty, you got an empty array $categories and you don't get this error.