Free Shipping method by Subtotal in WooCommerce

free_shipping_by_subtotal.php

<?php
/*********
 * Hooks
 * Remember to remove shipping-transient-version transient
 ********/

// Snippet 1 : Hide other shipping methods
add_filter( 'woocommerce_package_rates', 'maybeFreeShipping' );

// Snippet 2 : Notify that the customer can access free shipping.
add_action( 'woocommerce_before_cart', 'noticeFreeShipping' );
add_action( 'woocommerce_before_checkout_form', 'noticeFreeShipping' );



/**************
 * Functions
 **************/

/**
 * Hide other shipping methods
 * @param array $rates
 * @return array
 */
function maybeFreeShipping( array $rates ): array {
	
	$minFreeShipping = 100;
	$cartSubtotal    = WC()->cart->get_displayed_subtotal();
	
	// Return Early
	if ( $cartSubtotal < $minFreeShipping ) {
		return $rates;
	}

	// FreeShipping is visible
	foreach ( $rates as $rateID => $rate ) {
		if ( 'free_shipping' === $rate->method_id ) {
			continue;
		}
		
		unset( $rates[ $rateID ] );
	}
	
	return $rates;
}


/**
 * Print Notice on the cart and checkout page
 * @return void
 */
function noticeFreeShipping(): void {
	$minFreeShipping     = 100;
	$cartSubtotal        = WC()->cart->get_displayed_subtotal();
	
	// Return Early
	if ( $cartSubtotal >= $minFreeShipping ) {
		return;
	}
	
	$missingFreeShipping = $minFreeShipping - $cartSubtotal;
	
	printf(
		'<div class="woocommerce-info">%s</div>',
		sprintf(
			esc_html__( 'Agrega %s más a tu carrito para obtener el envío gratuito!', 'letsgo' ),
			wc_price( $missingFreeShipping )
		)
	);
}