Group custom posts by custom taxonomy names

Question

I try to display a list of custom posts grouped by categories using a solution from here (the 1st option/example). I adapted the code only a little to my needs, but it freezes (get a white display if it isn't commented) my installation/blog, because of this line (as it seems to me): $term_ids = array_map(function($t) { return $t->term_id, }, $terms);. I found that by commenting parts of the code. What is wrong with it?

My full code:

function yesterday_events2() {

    $terms = get_terms( 'event-categories' );

    $term_ids = array_map( function( $t ) { return $t->term_id }, $terms );

    $posts = get_posts(
        array(
            'nopaging'  => true,
            'tax_query' => array(
                array(
                    'taxonomy' => 'event-categories',
                    'field'    => 'id',
                    'terms'    => $term_ids,
            ) ),
    ) );

    foreach( $terms as $t ) {
        $posts_in_term = array_filter( $posts, function( $p ) use ( $t ) {
            // has_term likely triggers a DB hit...
            return has_term( $t->term_id, 'event-categories', $p );
        } );

        // do stuff with $posts_in_term 
    }

}

Answer 1

You should write it as the following:

$term_ids = array_map( function( $t ) { return $t->term_id ; }, $terms );

Also in the code, you have the get_terms where you directly write the taxonomy name. This has been deprecated in favor of the following :

$terms = get_terms( array(
    'taxonomy' => 'event-categories',
    'hide_empty' => false,
) );

Since 4.5.0, taxonomies should be passed via the ‘taxonomy’ argument in the $args array:

Second Question

About why you have an empty posts:

You are searching by default in the posts with post_type=post.

You should search for your custom post_type like this:

$posts = get_posts(
    array(
        'post_type' => 'custom_post_type',
        'nopaging'  => true,
        'tax_query' => array(
            array(
                'taxonomy' => 'event-categories',
                'terms'    => $term_ids ,
        ) ),
) );

I removed the 'field' => 'id' Because by default it gets the term_id and the accepted values are :

• 'term_id'
• 'name'
• 'slug'
• 'term_taxonomy_id'