How to use return instead of echo with this ACF snippet?

Question

I have a snippet to create bullet point for text area field.

However I was told I should use:

return $value

and not

echo

for anything in the acf/format_value hook. How can I make it in return $value format?

<?php

function my_acf_format_value( $value, $post_id, $field ) {
    $my_acf_format_value = explode("\n", $value);
    echo '<ol>';
    echo '<li>' . implode( '</li><li>', $my_acf_format_value) . '</li>';
    echo '</ol>';
}

add_filter('acf/format_value/name=pt_materials', 'my_acf_format_value', 10, 3);

Answer 1

Instead of using multiple echo statements, you can use string concatenation (.=) to join the strings together. Then at the end of the function, you can use the return statement to pass the value back to WordPress as required.

<?php

function my_acf_format_value( $value, $post_id, $field ) {
    $my_acf_format_value = explode("\n", $value);

    // Create string variable to append our data to
    $return_string = '';

    // Append values to our string variable.
    $return_string .= '<ol>';
    $return_string .= '<li>' . implode( '</li><li>', $my_acf_format_value) . '</li>';
    $return_string .= '</ol>';


    // Return the value
    return $return_string;

}

add_filter('acf/format_value/name=pt_materials', 'my_acf_format_value', 10, 3);
wordpress

I've added additional comments to explain the steps involved, but since this is such a simple function, this could be done with a single line of code:

return '<ol><li>' . implode( '</li><li>', $my_acf_format_value) . '</li></ol>';