Leaflet Map Media Queries

Question

I am trying to make a map media query for phones and make the zoom decrease to 8. However, this doesn't seem to work, the map doesn't decrease zoom when I set the width, is there any error in this code?

 window.addEventListener('resize', function(event){
    var width = this.document.documentElement.clientWidth;
    console.log(width);
    if (width < 376) {
      map.setZoom(8);
    } else {
      map.setZoom(10); 
    }
});