Minify and Support modern JavaScript syntax

[rderik]

Is your feature request related to a problem? Please describe.

We are currently serving multiple plain JavaScript files. These files can be minified and bundled together to serve one compressed file, improving front end performance for all of our visitors.

We could also take advantage of modern JavaScript if we transpile the code from ES6 or ES7 to vanilla JavaScript so it can be understood even by old browsers.

Describe the solution you'd like

Improve the way we handle JavaScript in the project so we can provide a better User Experience and at the same time improve developer efficiency by taking advantage of modern JavaScript techniques.

Describe alternatives you've considered

We could refactor/migrate all of our code to ES6 or ES7 JavaScript, but that would take more time and effort.

Additional context
N/A