Access ACF fields within custom preview function?

I’d like to access custom ACF field values from custom_preview() filter?

add_filter( 'preview_post_link', 'custom_preview' );

function custom_preview() {
    // how to access ACF field values here ?
}

Answers:

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Method 1

As documented, the preview_post_link passes the post object as the second parameter. You can use this to get any fields that you might want:

add_filter(
    'preview_post_link',
    function( $preview_link, $post ) {
        $custom_field = get_field( 'custom_field_name', $post );
        
        return $preview_link;
    },
    10,
    2 // MUST be 2 to get the $post parameter.
);

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0