Open Minicart When Item Is Added In Magento2

vendor/magento/Magento_Checkout/view/web/js/view/minicart.js

Under initialize: function, you will see

$('[data-block="minicart"]').on('contentLoading', function (event) {

Replace the function with this code.

$('[data-block="minicart"]').on('contentLoading', function (event) {
            addToCartCalls++;
            self.isLoading(true);
            $('[data-block="minicart"]').on('contentUpdated', function ()  {
                $('[data-block="minicart"]').find('[data-role="dropdownDialog"]').dropdownDialog("open");       
                setTimeout(function() {
                $('[data-block="minicart"]').find('[data-role="dropdownDialog"]').dropdownDialog("close");
            }, 4000);
            });
        });