MatchMedia not working when browser window is resized?

Question

JavaScript

If you resize the browser window and refresh the page, everything works, but the listener does not work when the window is resized.
codepen.io/azat-io/pen/oxogRJ

Answer 1

Short abstract example

var mediaQuery = window.matchMedia("screen and (min-width: 855px)");
mediaQuery.addListener(myFunc);

function myFunc(mq) {
    if (mq.matches) {
    	document.body.style.backgroundColor = '#060';
    } else {
    document.body.style.backgroundColor = '#900';
    }
}
myFunc(mediaQuery);