Magento 2 checkout page where is coming from a order summary section's data in payment step?

Question

Checkout page it displays order summary section.It has Product data displaying .Product infromation coming from Magento\Checkout\Model\DefaultConfigProvider.php and from getTotalsData() function if it is in shipping step and when I switch in payment step order summary section display product information but it is not coming from getTotals() in payment section.

If I change code from $output['totalsData'] = $this->getTotalsData() to $output['totalsData'] = array() in getConfig() function so result is order summary product section not display in checkout shipping step but it displays in payment step

I have added following code in file: pub\static\frontend\Magento\luma\en_US\Magento_Checkout\template\summary\item

<pre data-bind="text: ko.toJSON($parent, null, 2)"></pre>

And display following result in checkout page:- I have changed code in getTotalsData() function in Magento\Checkout\Model\DefaultConfigProvider.php path and add isbn attribute in totalsdata object but not diplay in payment step but it display in shipping step

Shipping Step 1: https://i.sstatic.net/hFV0t.jpg This above shipping step screenshot where it display totals information and also display my custom product attribute 'isbn'.

Payment Step 1: https://i.sstatic.net/GlIe7.jpg This above shipping step screenshot where it display totals information and not display my custom product attribute 'isbn'.

I have changed in core file DefaultconfigProvider.php temporary to check

And changed only this getTotalsData() function

private function getTotalsData()
    {
        /** @var \Magento\Quote\Api\Data\TotalsInterface $totals */
        $totals = $this->cartTotalRepository->get($this->checkoutSession->getQuote()->getId());
        $items = [];
        /** @var  \Magento\Quote\Model\Cart\Totals\Item $item */
        foreach ($totals->getItems() as $item) {
            $data = $item->__toArray(); // custom code
            $data['isbn'] = 'ISBN-12345'; // custom code
            $items[] = $data;
        }
        $totalSegmentsData = [];
        /** @var \Magento\Quote\Model\Cart\TotalSegment $totalSegment */
        foreach ($totals->getTotalSegments() as $totalSegment) {
            $totalSegmentArray = $totalSegment->toArray();
            if (is_object($totalSegment->getExtensionAttributes())) {
                $totalSegmentArray['extension_attributes'] = $totalSegment->getExtensionAttributes()->__toArray();
            }
            $totalSegmentsData[] = $totalSegmentArray;
        }
        $totals->setItems($items);
        $totals->setTotalSegments($totalSegmentsData);
        $totalsArray = $totals->toArray();
        if (is_object($totals->getExtensionAttributes())) {
            $totalsArray['extension_attributes'] = $totals->getExtensionAttributes()->__toArray();
        }
        return $totalsArray;
    }

And this is my details.html file which I have modified

<!--
/**
 * Copyright © 2016 Magento. All rights reserved.
 * See COPYING.txt for license details.
 */
-->

<!-- ko foreach: getRegion('before_details') -->
    <!-- ko template: getTemplate() --><!-- /ko -->
<!-- /ko -->
<div class="product-item-details">

    <div class="product-item-inner">
        <div class="product-item-name-block">
            <strong class="product-item-name" data-bind="text: $parent.name"></strong>
            <div class="details-qty">
                <span class="label"><!-- ko i18n: 'Qty' --><!-- /ko --></span>
                <span class="value" data-bind="text: $parent.qty"></span>
            </div>
            <div class="details-isbn">
                <span class="label"><!-- ko i18n: 'Isbn' --><!-- /ko --></span>
                <span class="value" data-bind="text: $parent.isbn"></span>
            </div>
        </div>
        <!-- ko foreach: getRegion('after_details') -->
            <!-- ko template: getTemplate() --><!-- /ko -->
        <!-- /ko -->
    </div>

    <!-- ko if: (JSON.parse($parent.options).length > 0)-->
    <div class="product options" data-bind="mageInit: {'collapsible':{'openedState': 'active'}}">
        <span data-role="title" class="toggle"><!-- ko i18n: 'View Details' --><!-- /ko --></span>
        <div data-role="content" class="content">
            <strong class="subtitle"><!-- ko i18n: 'Options Details' --><!-- /ko --></strong>
            <dl class="item-options">
                <!--ko foreach: JSON.parse($parent.options)-->
                <dt class="label" data-bind="text: label"></dt>
                    <!-- ko if: ($data.full_view)-->
                    <dd class="values" data-bind="html: full_view"></dd>
                    <!-- /ko -->
                    <!-- ko ifnot: ($data.full_view)-->
                    <dd class="values" data-bind="html: value"></dd>
                    <!-- /ko -->
                <!-- /ko -->
            </dl>
        </div>
    </div>
    <!-- /ko -->
</div>

In payment step,product information where is coming from ?

Answer 1

You can set your custom attribute inside checkout page summary block using below way,

app/code/{Package}/{Module}/etc/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">    
    <!-- Set Custom attribute in chekcout page summary block -->
    <type name="Magento\Checkout\Model\DefaultConfigProvider">
        <plugin name="default_config_provider" type="Package\Module\Model\DefaultConfigProvider"/>
    </type>
</config>

app/code/{Package}/{Module}/Model/DefaultConfigProvider.php file

<?php
namespace Package\Module\Model;

use Magento\Checkout\Model\Session as CheckoutSession;
use Magento\Quote\Api\CartItemRepositoryInterface as QuoteItemRepository;

class DefaultConfigProvider
{
    private $checkoutSession;
    private $quoteItemRepository;
    protected $scopeConfig;

    public function __construct(
        CheckoutSession $checkoutSession,
        QuoteItemRepository $quoteItemRepository,
        \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig
    ) {
        $this->_scopeConfig = $scopeConfig;
        $this->checkoutSession = $checkoutSession;
        $this->quoteItemRepository = $quoteItemRepository;
    }

    public function afterGetConfig(\Magento\Checkout\Model\DefaultConfigProvider $subject, $result)
    {        
        $quoteId = $this->checkoutSession->getQuote()->getId();
        if ($quoteId) {            
            $itemOptionCount = count($result['totalsData']['items']);
            $quoteItems = $this->quoteItemRepository->getList($quoteId);

            $isbnOptions = array();
            foreach ($quoteItems as $index => $quoteItem) {
                $quoteItemId = $quoteItem['item_id'];
                $isbnOptions[$quoteItemId] = $quoteItem['isbn'];               
            }

            for($i=0;$i<$itemOptionCount;$i++){
                $quoteParentId = $result['totalsData']['items'][$i]['item_id'];                    
                $currentOption = array();
                $currentOption = json_decode($result['totalsData']['items'][$i]['options'],true);

                $newOption = $isbnOptions[$quoteParentId];

                //for set new option inside current option tab
                if(count($newOption) > 0 && is_array($newOption)){                        
                    foreach($newOption as $key=>$value){
                        if( !is_array($value) ){
                            $currentOption[] = array('value'=>$value,'label'=>$key);
                        }
                    }
                    $result['totalsData']['items'][$i]['options'] = json_encode($currentOption);
                }                    
            }
        }
        return $result;
    }
}

Answer 2

Product information is in $output['totalsData']

vendor/magento/module-checkout/Model/DefaultConfigProvider.php

public function getConfig()
{ 
    ......

    $output['totalsData'] = $this->getTotalsData();
    ......
}

You should read more here: https://magento.stackexchange.com/a/133732/33057