Add rating to LocalBusiness Schema

Use this code when using local schemas:

// Add rating to LocalBusiness Schema
add_filter( 'rank_math/snippet/rich_snippet_localbusiness_entity', function( $entity ) {
    // If you use custom fields, grab the dynamic values here
    // Example: $rating = get_post_meta(get_the_ID(), 'business_rating', true);
    
    $entity['aggregateRating'] = [
        '@type'       => 'AggregateRating',
        'ratingValue' => '4.8', // Replace with dynamic variable if needed
        'reviewCount' => '150', // Replace with dynamic variable if needed
        'bestRating'  => '5',
        'worstRating' => '1',
    ];

    return $entity;
});

Use this code when using global LocalBusiness Schema:

add_filter( 'rank_math/json_ld', function( $data, $jsonld ) {
    // Check if Rank Math's LocalBusiness schema is present in the output array
    if ( ! empty( $data['LocalBusiness'] ) ) {
        
        // Inject the aggregateRating array directly into it
        $data['LocalBusiness']['aggregateRating'] = [
            '@type'       => 'AggregateRating',
            'ratingValue' => '4.9', // Replace with your dynamic value or ACF field
            'reviewCount' => '142', // Replace with your dynamic value or ACF field
            'bestRating'  => '5',
            'worstRating' => '1',
        ];
    }
    return $data;
}, 99, 2 ); // Priority 99 ensures this runs after Rank Math finishes compiling data

You can use both at the same time.

Rank Math sometimes groups Organization and LocalBusiness into 1 array so this might work instead:

add_filter( 'rank_math/json_ld', function( $data, $jsonld ) {
    // Check if the schema graph exists and is an array
    if ( ! empty( $data['@graph'] ) && is_array( $data['@graph'] ) ) {
        
        // Loop through each schema object in the graph
        foreach ( $data['@graph'] as $key => $schema_item ) {
            
            // Check if the item contains the @type property
            if ( ! empty( $schema_item['@type'] ) ) {
                
                // Get the type(s) as an array to handle the ["LocalBusiness", "Organization"] setup
                $types = (array) $schema_item['@type'];
                
                // If it is our local business block, inject the rating properties
                if ( in_array( 'LocalBusiness', $types ) ) {
                    $data['@graph'][$key]['aggregateRating'] = [
                        '@type'       => 'AggregateRating',
                        'ratingValue' => '4.9', // Replace with your dynamic value or ACF field
                        'reviewCount' => '142', // Replace with your dynamic value or ACF field
                        'bestRating'  => '5',
                        'worstRating' => '1',
                    ];
                    break; // Stop looping once found and updated
                }
            }
        }
    }
    return $data;
}, 99, 2 );