Cart ajax: apply coupon

Adds an ajax call for applying coupons while on the cart
screen (not checkout, as it already has this.)

This is the first commit to add ajax calls to the cart update
functions. See issue woocommerce#6734

assets/js/frontend/cart.js

@@ -37,4 +37,52 @@ jQuery( function( $ ) {
 	});
 
 	$( '.shipping-calculator-form' ).hide();
+
+	// Update the cart after something has changed.
+	var update_cart_totals = function() {
+		$( 'div.cart_totals' ).block({
+			message: null,
+			overlayCSS: {
+				background: '#fff',
+				opacity: 0.6
+			}
+		});
+
+		var url = wc_cart_params.wc_ajax_url.toString().replace( '%%endpoint%%', 'get_cart_totals' );
+
+		$.ajax( {
+			url:     url,
+			success: function( response ) {
+				$( 'div.cart_totals' ).replaceWith( response );
+			}
+		});
+	};
+
+	// Coupon code
+	$( '[name="apply_coupon"]' ).on( 'click', function( evt ) {
+		evt.preventDefault();
+
+		var text_field = $( '#coupon_code' );
+		var coupon_code = text_field.val();
+		text_field.val( '' );
+
+		var url = wc_cart_params.wc_ajax_url.toString().replace( '%%endpoint%%', 'apply_coupon' );
+		var data = {
+			security: wc_cart_params.apply_coupon_nonce,
+			coupon_code: coupon_code
+		};
+
+		$.ajax( {
+			type:    'POST',
+			url:     url,
+			data:    data,
+			success: function( response ) {
+				window.console.log( 'apply coupon response:' );
+				window.console.log( response );
+			},
+			complete: function() {
+				update_cart_totals();
+			}
+		});
+	});
 });

includes/class-wc-ajax.php

@@ -94,6 +94,7 @@ public static function add_ajax_events() {
 			'apply_coupon'                                     => true,
 			'remove_coupon'                                    => true,
 			'update_shipping_method'                           => true,
+			'get_cart_totals'                                  => true,
 			'update_order_review'                              => true,
 			'add_to_cart'                                      => true,
 			'checkout'                                         => true,
@@ -254,6 +255,22 @@ public static function update_shipping_method() {
 		die();
 	}
 
+	/**
+	 * AJAX receive updated cart_totals div.
+	 */
+	public static function get_cart_totals() {
+
+		if ( !defined( 'WOOCOMMERCE_CART' ) ) {
+			define( 'WOOCOMMERCE_CART', true );
+		}
+
+		WC()->cart->calculate_totals();
+
+		woocommerce_cart_totals();
+
+		die();
+	}
+
 	/**
 	 * AJAX update order review on checkout.
 	 */

includes/class-wc-frontend-scripts.php

@@ -289,6 +289,7 @@ private static function get_script_data( $handle ) {
 					'ajax_url'                     => WC()->ajax_url(),
 					'wc_ajax_url'                  => WC_AJAX::get_endpoint( "%%endpoint%%" ),
 					'update_shipping_method_nonce' => wp_create_nonce( "update-shipping-method" ),
+					'apply_coupon_nonce'           => wp_create_nonce( "apply-coupon" ),
 				);
 			break;
 			case 'wc-cart-fragments' :