Translating static text in JavaScript files
For now I'm going with this solution:

&lt;script&gt;

    var translatedLabels = {
        'name' : {{'Uw naam'|translate}},
        'email' : {{'Uw e-mail adres'|translate}},
        'email_receiver' : {{'E-mail adres van de ontvanger'|translate}},
    }

&lt;/script&gt;


The above is in a template file that gets included on the relevant pages, if it turns out I'll need those or other translated texts in multiple parts of the website, I might just include it in the basic layout directly. 

It allows me to keep doing the translations from the backend with that translation plugin and I can now use the translated messages in my Javascript generated HTML.