screen.js

export const detectZoom = () => {
    let ratio = 0,
      screen = window.screen,
      ua = navigator.userAgent.toLowerCase();
    if (window.devicePixelRatio !== undefined) {
      ratio = window.devicePixelRatio;
    } else if (~ua.indexOf('msie')) {
      if (screen.deviceXDPI && screen.logicalXDPI) {
        ratio = screen.deviceXDPI / screen.logicalXDPI;
      }
    } else if (
      window.outerWidth !== undefined &&
      window.innerWidth !== undefined
    ) {
      ratio = window.outerWidth / window.innerWidth;
    }
    if (ratio) {
      ratio = Math.round(ratio * 100);
    }
    return ratio;
  };