Issue #3275592 by SirClickALot, mxh: Working, but not working?

This module helps frontend developers by exposing the breakpoints

as Javascript variables, being directly accessible via

<code>window.themeBreakpoints</code>.

`window.themeBreakpoints`.

The function <code>themeBreakpoints.getCurrentBreakpoint()</code>

The function `themeBreakpoints.getCurrentBreakpoint()`

tells you the currently matching breakpoint for the given client.

A new event <code>themeBreakpoint:changed</code> is being provided, which fires

A new event `themeBreakpoint:changed` is being provided, which fires

when the matching breakpoint of the client has changed. With this event, you're

able to implement responsive Javascript behaviors via event listeners.

Example event listener with JQuery:

<code>

$(window).on('themeBreakpoint:changed', function (event, breakpoint) {

  alert('The current breakpoint has been changed to ' + breakpoint.name);

Example listener:

```javascript

window.addEventListener('themeBreakpoint:changed', function (event) {

  alert('The current breakpoint has been changed to ' + event.detail.name);

});

</code>

```

Backend developers can use the <code>theme_breakpoints_js</code>

Backend developers can use the `theme_breakpoints_js`

service for conveniently receiving breakpoints defined by themes.

It already takes care about defined breakpoints by base themes and also

loads them in case a theme doesn't define breakpoints by itself.