Magento2

We will show here how we can display a private content in a full cached page, it is very useful if you want to display information per customer 
Magento loads sections by AJAX request to /customer/section/load/ and caches loaded data in the browser local storage under the key mage-cache-storage. Magento tracks when some section is changed and load updated section automatically.

We will use this Vendor/Module as names

Go to Admin => Stores > Configuration > Catalog > Catalog > Recently Viewed/Compared Products select Yes to ( Synchronize widget products with backend storage )
 

Unable to save address. Please check input data.

It's a strange error we have it sometime, to solve it in some cases you execute this query 

SELECT entity_id, customer_id FROM quote WHERE customer_id != 0 AND customer_is_guest = 1;

and then update the records by this query 

UPDATE quote SET customer_is_guest = 0 WHERE customer_id != 0 AND customer_is_guest = 1;

reference url :

https://stackoverflow.com/a/58086757/4135373

the best way is to work on your custom theme by modifying these files

/app/design/frontend/{Vendor}/{theme}/Magento_Checkout/layout/checkout_index_index.xml

To do this we need to work on the design area it is the easiest way 

firs Create new folder under your theme 

Folder Name: Magento_ConfigurableProduct\web\js

Copy this file "configurable.js" from this path

vendor/magento/module-configurable-product/view/frontend/web/js/configurable.js 

in the line 407 you need to modify this part

In this wiki we will find a way to use "==" equal in the email template, actually there is no equal in the email template itself but we can refer to a phtml file and pass a variable to it then use the if/equal in the phtml file to do this you can easily add this code to the template 

in the below example we will check if the payment method is bank transfer then we will write something

- Where does Magento Check the email frequency send

\vendor\magento\module-security\Model\SecurityChecker\Frequency.php

public function check($securityEventType, $accountReference = null, $longIp = null)
{

}

- 

First of all you need to install Mageplaza Extension , you can find it here

https://github.com/mageplaza/magento-2-smtp

after you create O365 SMTP connector that you may use as smtp server to allow sending out emails as group

you need to override this class

vendor\mageplaza\module-smtp\Model\Config\Source\Authentication.php

change value of None from '' into 'smtp'.

then go to the configuration and choose None and click on Save

that's it :)

You need to use this in your constructer 

/**
 * @var Magento\Framework\Registry
 */
private $registry;

public function __construct(\Magento\Framework\Registry $registry)

{
    $this->registry = $registry;
}

then you can get the current category by this code

$category = $this->registry->registry('current_category');