Magento 2 – How to Translate String in Function in Knockout Template

I found solution for CSV translates, but not for inline.

1. Add to CSV:

"This is a required field.","This is a required field!!!"

2. Add code to phtml:

<script>
require([
    'jquery',
    'mage/translate'
], function ($) {
    $(window).load(function () {
        var translates = <?php echo \Zend_Json::encode(
            array(
                'This is a required field.' => __('This is a required field.'),
            )
        )?>;
        $.mage.translate.add(translates);
    });
});
</script>

The initObservable method sets up variable tracking, as described in this article. In short: this lets you make an property a Knockout observable property by listing it as a tracks default. Knockout observable properties can update the UI automatically whenever they, themselves, are updated.

The initObservable method is called in the uiElement's initialize method. The initialize method is a __constructor/_construct style method for Magento's custom javascript object system.

#File: vendor/magento/module-ui/view/base/web/js/lib/core/element/element.js
initialize: function () {
    this._super()
        .initObservable()
        .initModules()
        .initStatefull()
        .initLinks()
        .initUnique();

    return this;
},

If you're curious about this object system, the UI Components and uiElement Internals series are a good place to start.