Magento 2 - Update quantity and totals of cart page without page reload?

Question

In Magento2 - We need to update main cart on change of quantity by Ajax without click on "Update Cart Button" and without reloading the page, Below my code in this code only update cart subtotal but not updated cart page summery sidebar subtotal.

 require(['jquery', 'Magento_Customer/js/customer-data',
    'jquery/jquery-storageapi'], function ($) {
    // $("#submitbutton").hide();
    var form = $('form#form-validate');
    var qtyfields = $('input.qty');
    $('.page.messages').each(function () {
        var thismessage = $(this);
        thismessage.attr('id', 'messages');
    });

    form.find(qtyfields).each(function (e) {
        var thisfield = $(this);
        $(this).change(function () {
            console.log('change detected');
            form.submit();
        });

    });
    $(document).on('submit','form#form-validate', function (e) {
        var thisfield = $(this);
        var thisiteminfo = thisfield.closest(".item-info");
        var thissubtotal = thisiteminfo.children(".subtotal");
        var formsubtotals = $(this).find('.subtotal');
        e.preventDefault();
        $.ajax({
            url: form.attr('action'),
            data: form.serialize(),
            type: 'post',
            success: function (res) {
                var parsedResponse = $.parseHTML(res);
                var result = $(parsedResponse).find("#form-validate");
                $("#form-validate").replaceWith(result);
                var totals = $(parsedResponse).find("#cart-totals");
                $("#cart-totals").replaceWith(totals);
                console.log(totals);
                //location.reload();
            },
            error: function () {
                console.log('error');
            }
        });
        console.log('form submitted');
    });
}); 

Please help me for find best solution.

Answer 1

Have you tried deferred operation with getTotalsAction or totals-processor?

It's showing ajax process in your cart after calcul

you can use it like this (i minimize your code, just to show you how to use these functions.) :

require(["jquery", "Magento_Customer/js/customer-data","jquery/jquery-storageapi","Magento_Checkout/js/model/cart/totals-processor/default","Magento_Checkout/js/model/cart/cache","Magento_Checkout/js/model/quote","Magento_Checkout/js/action/get-totals"], function ($,defaultTotal,cartCache,quote,getTotalsAction) {
$(document).on("submit","form#form-validate", function (e) {
    e.preventDefault();
    $.ajax({
        url: form.attr("action"),
        data: form.serialize(),
        type: "post",
        success: function (res) {

    var deferred = $.Deferred();
    // this show ajax loader and reload price in cart
    getTotalsAction([], deferred);
    // this one too 
    defaultTotal.estimateTotals();
        },
        error: function () {
            console.log("error");
        }
    });
    console.log("form submitted");
});}); 

I suggest you to show this post for updating price in cart : How to add fee to order totals in Magento 2 and this one : https://github.com/sivajik34/Custom-Fee-Magento2