custom-fields.md

Custom fields

When using custom fields (e.g. with the Advanced Custom fields plugin) you might have to register a filter to convert array style configs to plain values.

By default, the plugin saves custom fields in an array structure that is exported as:

["my-bool"]=>
    array(1) {
        [0] => string(1) "1"
    }
["location"]=>
    array(1) {
        [0] => string(88) "My address"
    }

And this leads to a YAML structure like:

my-bool:
- "1"
location:
- 'My address'

This is likely not the structure you expect or want to work with. You can convert it using a filter:

add_filter( 'jekyll_export_meta', function($meta) {
    foreach ($meta as $key => $value) {
        if (is_array($value) && count($value) === 1 && array_key_exists(0, $value)) {
            $meta[$key] = $value[0];
        }
    }

    return $meta;
});

A more complete solution could look like that:

add_filter( 'jekyll_export_meta', function($meta) {
    foreach ($meta as $key => $value) {
        // Advanced Custom Fields
        if (is_array($value) && count($value) === 1 && array_key_exists(0, $value)) {
            $value = maybe_unserialize($value[0]);
            // Advanced Custom Fields: NextGEN Gallery Field add-on
            if (is_array($value) && count($value) === 1 && array_key_exists(0, $value)) {
                $value = $value[0];
            }
        }
        // convert types
        $value = match ($key) {
            // Advanced Custom Fields: "true_false" type
            'my-bool' => (bool) $value,
            default => $value
        };
        $meta[$key] = $value;
    }

    return $meta;
});