Magento – Magento2: How to get guest email address in checkout

Try this:

In your config.xml file:

<config>
<global>
.........
   <events>
            <sales_order_place_after>
                <observers>
                    <any_name>
                        <type>singleton</type>
                        <class>Namespace_ModuleName_Model_Observer</class>
                        <method>getEmail</method>
                    </any_name>
                </observers>
            </sales_order_place_after>
   </events>
..........
</global>
</config>

Then in your Model/Observer.php:

public function getEmail($observer){
   $order= $observer->getEvent()->getOrder();
   if($order->getCustomerId()){
       $email = $order->getCustomerEmail(); //logged in customer
   }
   else{
       $email = $order->getBillingAddress()->getEmail(); //not logged in customer
   }

   //your other logic

   //lets test if it is grabbing email
   Mage::log($order->getId(). " - ". $email, null, 'your_name.log');
}

This will create a file named your_name.log in var/log folder when anyone places order.

If everything is ok, then you will see your customer's email in that file.

Good luck.

This is the solution, you can get guest and customer informations in checkout , inject Magento_Checkout/js/model/quote on your view method.

define(
    [
        'jquery',
        'Magento_Checkout/js/view/payment/default',
        'Magento_Checkout/js/model/quote',
        'Magento_Checkout/js/action/place-order',
    ],
    function ($,Component,quote,placeOrderAction) {
        'use strict';

        return Component.extend({

            defaults: {
                template: 'Path/to/your/template'
            },

            getEmail: function () {
                if(quote.guestEmail) return quote.guestEmail;
                else return window.checkoutConfig.customerData.email;
            },

            getLastName: function () {
                return quote.billingAddress().lastname;
            },

            getFirstName: function () {
                return quote.billingAddress().firstname;
            },

            getAddress: function () {
                return quote.billingAddress().street[0]+", "+quote.billingAddress().postcode+" "+quote.billingAddress().city+", Maroc";
            },

            getPhone: function () {
                return quote.billingAddress().telephone;
            },

        });
    }
);