Change wc_cart_totals_shipping_method_label function in Woocommerce - php

Question

Inside Woocommerce plugin on the includes subfolder, there's a file wc-cart-functions.php.
I would like to change the function wc_cart_totals_shipping_method_label(), but I am not allowed to copy the function to my theme's functions.php. I believe I have to use a custom action/filter to change this core function, but no idea how to do that.
Original function:
function wc_cart_totals_shipping_method_label( $method ) {
$label = $method->get_label();
$has_cost = 0 < $method->cost;
$hide_cost = ! $has_cost && in_array( $method->get_method_id(), array( 'free_shipping', 'local_pickup' ), true );
if ( $has_cost && ! $hide_cost ) {
if ( WC()->cart->display_prices_including_tax() ) {
$label .= ': ' . wc_price( $method->cost + $method->get_shipping_tax() );
if ( $method->get_shipping_tax() > 0 && ! wc_prices_include_tax() ) {
$label .= ' <small class="tax_label">' . WC()->countries->inc_tax_or_vat() . '</small>';
}
} else {
$label .= ': ' . wc_price( $method->cost );
if ( $method->get_shipping_tax() > 0 && wc_prices_include_tax() ) {
$label .= ' <small class="tax_label">' . WC()->countries->ex_tax_or_vat() . '</small>';
}
}
}
return apply_filters( 'woocommerce_cart_shipping_method_full_label', $label, $method );
}
What the function should be:
function wc_cart_totals_shipping_method_label( $method ) {
$label = $method->get_label();
$has_cost = 0 < $method->cost;
$hide_cost = ! $has_cost && in_array( $method->get_method_id(), array( 'free_shipping', 'local_pickup' ), true );
if ( $has_cost && ! $hide_cost ) {
if ( WC()->cart->display_prices_including_tax() ) {
$label .= ': ' . wc_price( $method->cost + $method->get_shipping_tax() );
if ( $method->get_shipping_tax() > 0 && ! wc_prices_include_tax() ) {
$label .= ' <small class="tax_label">' . WC()->countries->inc_tax_or_vat() . '</small>';
}
} else {
$label .= ': ' . wc_price( $method->cost );
if ( $method->get_shipping_tax() > 0 && wc_prices_include_tax() ) {
$label .= ' <small class="tax_label">' . WC()->countries->ex_tax_or_vat() . '</small>';
}
}
}
/* Here's the code I want added */
elseif ( ! $has_cost && ! $hide_cost ) {
$label .= ': Free';
}
return apply_filters( 'woocommerce_cart_shipping_method_full_label', $label, $method );
}
What I want to do:
Shipping methods that have zero cost should have "Free" added to their label. Right now there's nothing shown beside the method title.
How can I make the necessary changes to this function, without overwriting Woocommerce core files?

Answer 1

As you can see in this function you can use woocommerce_cart_shipping_method_full_label filter hook, to manage that change, this way:
add_filter( 'woocommerce_cart_shipping_method_full_label', 'change_cart_shipping_method_full_label', 10, 2 );
function change_cart_shipping_method_full_label( $label, $method ) {
$has_cost = 0 < $method->cost;
$hide_cost = ! $has_cost && in_array( $method->get_method_id(), array( 'free_shipping', 'local_pickup' ), true );
if ( ! $has_cost && ! $hide_cost ) {
$label = $method->get_label() . ': Free';
}
return $label;
}
Code goes in function.php file of your active child theme (or active theme). Tested and works.