php - How should I change the woocommerce_form_field HTML Structure?

Question

I'm using WooCommerce: Add Checkout Fees Based on Custom Radio Button from businessbloomer

My question is about woocommerce_form_field() which is used in part 1

// etc...
echo '<div id="checkout-radio">';
echo '<h3>Customize Your Order!</h3>';
woocommerce_form_field( 'radio_choice', $args, $chosen );
echo '</div>';
// etc...

The structure of the HTML that woocommerce_form_field( 'radio_choice', $args, $chosen ); outputs is

<p class="form-row form-row-wide update_totals_on_change" id="radio_choice_field" data-priority="">
    <span class="woocommerce-input-wrapper"> 
        <input type="radio" class="input-radio " value="0" name="radio_choice" id="radio_choice_0">
        <label for="radio_choice_0" class="radio ">No Option</label>
        <input type="radio" class="input-radio " value="10" name="radio_choice" id="radio_choice_10">
        <label for="radio_choice_10" class="radio ">Option 1 ($10)</label>
        <input type="radio" class="input-radio " value="30" name="radio_choice" id="radio_choice_30" checked="checked">
        <label for="radio_choice_30" class="radio ">Option 2 ($30)</label> 
    </span>
</p>

The structure that I'm trying to get is this:

<div>
    <ul>
        <!-- here every element which is gonna be type radio needs to be with It's label in a <li> element -->

        <li>
            <input type='radio'> </input>
            <label>No option</label>
        </li>
        <li>
            <input type='radio'> </input>
            <label>Option 2</label>
        </li>
        <li>
            <input type='radio'> </input>
            <label>Option 2</label>
        </li>

    </ul>
</div>

---

I searched for a solution but I could find one for the radio button

Answer 1

To rewrite the output html from the woocommerce_form_field function there are 2 filter hooks available:

1. Filter by type: here we can specify the $args['type'] like text, password, datetime, select, radio, etc...

/**
 * Filter by type.
 */
$field = apply_filters( 'woocommerce_form_field_' . $args['type'], $field, $key, $args, $value );

2. General filter on form fields: a general filter where we can then add an if condition to apply this to a specific type of field

/**
 * General filter on form fields.
 *
 * @since 3.4.0
 */
$field = apply_filters( 'woocommerce_form_field', $field, $key, $args, $value );

---

The first option seems most suitable for your question

So

apply_filters( 'woocommerce_form_field_' . $args['type']...

Is going to be ( Where $args['type'] is equal to radio )

function filter_woocommerce_form_field_radio( $field, $key, $args, $value ) {
    // Do something
    return $field;
}
add_filter( 'woocommerce_form_field_radio', 'filter_woocommerce_form_field_radio', 10, 4 );

The callback function uses $field which contains all HTML from <p> to the closing </p> HTML tag, so we have the ability to rewrite the entire output of this through our function

---

Source used for this answer: wc-template-functions.php#L2847-L2850, note the use of $args with which the code can be dynamically constructed.

(This code was copied from wc-template-functions.php line 2847 - 2850)

foreach ( $args['options'] as $option_key => $option_text ) {
    $field .= '<input type="radio" class="input-radio ' . esc_attr( implode( ' ', $args['input_class'] ) ) . '" value="' . esc_attr( $option_key ) . '" name="' . esc_attr( $key ) . '" ' . implode( ' ', $custom_attributes ) . ' id="' . esc_attr( $args['id'] ) . '_' . esc_attr( $option_key ) . '"' . checked( $value, $option_key, false ) . ' />';
    $field .= '<label for="' . esc_attr( $args['id'] ) . '_' . esc_attr( $option_key ) . '" class="radio ' . implode( ' ', $args['label_class'] ) . '">' . esc_html( $option_text ) . '</label>';
}

---

So to answer your question: We get, based on the $key so that it is applied only for that specific piece

function filter_woocommerce_form_field_radio( $field, $key, $args, $value ) {
    // Based on key
    if ( $key == 'radio_choice' ) {
        if ( ! empty( $args['options'] ) ) {
            
            $field = '<div><ul>';
            
            foreach ( $args['options'] as $option_key => $option_text ) {
                $field .= '<li>';
                $field .= '<input type="radio" value="' . esc_attr( $option_key ) . '" name="' . esc_attr( $key ) . '" id="' . esc_attr( $args['id'] ) . '_' . esc_attr( $option_key ) . '" />';
                $field .= '<label>' . esc_html( $option_text ) . '</label>';
                $field .= '</li>';
            }
            
            $field .= '</ul></div>';
        }
    }
    
    return $field;
}
add_filter( 'woocommerce_form_field_radio', 'filter_woocommerce_form_field_radio', 10, 4 );

Output:

<div>
    <ul>
        <li>
            <input type="radio" value="0" name="radio_choice" id="radio_choice_0">                                    
            <label>No Option</label>
        </li>
        <li>
            <input type="radio" value="10" name="radio_choice" id="radio_choice_10">        
            <label>Option 1 ($10)</label>
        </li>
        <li>
            <input type="radio" value="30" name="radio_choice" id="radio_choice_30">
            <label>Option 2 ($30)</label>
        </li>
    </ul>
</div>