Magento 2: language pack not working properly after .csv file was edited

Question

I installed this language pack https://github.com/splendidinternet/Magento2_German_LocalePack_de_DE. Everything worked fine.

Then I edited the following line in the magento-path\app\i18n\splendid\de_DE\de_DE.csv file:

"Add to Cart,Zum Warenkorb hinzufügen -> Add to Cart,In den Warenkorb"

When I go to category page, at first everything looks fine:

but when I click on the 'add to cart'(In den Warenkorb) button , the button text changes back to the translation "Zum Warenkorb hinzufügen", which was there before I edited the de_DE.csv file:

When I reload the site everything looks good again:

I think it has something to do with JS. Any hints on solving this issue ?

UPDATE: Changed Code in pub\static\frontend\<vendor>\<theme>\de_DE\Magento_Catalog\j‌​s\catalog-a‌​dd-to-cart.js:

setTimeout(function() {
                var addToCartButtonTextDefault = 'In den Warenkorb'; //changed
                console.log("test1");         addToCartButton.removeClass(self.options.addToCartButtonDisabledClass);
                addToCartButton.find('span').text(addToCartButtonTextDefault);
                console.log("test2");
                addToCartButton.attr('title', addToCartButtonTextDefault);
            }, 1000);

Now it works

Answer 1

Take a look: vendor/magento/module-catalog/view/frontend/web/js/catalog-add-to-cart.js. As we can see, Magento uses Ajax for adding product to cart. In each state, there are some different texts:

$t('Adding...')
$t('Added')
$t('Add to Cart')

So, we need to translate for these texts.