is.js - es6 - just browser detection, nothing elese

is.js

// based on https://github.com/arasatasaygin/is.js/blob/master/is.js
// this is a cut off minimal version

const userAgent = (navigator && navigator.userAgent.toLowerCase()) || '';
const vendor = (navigator && navigator.vendor || '').toLowerCase();

// build a 'comparator' object for various comparison checks
const comparator = {
  '<': (a, b) => a < b,
  '<=': (a, b) => a <= b,
  '>': (a, b) => a > b,
  '>=': (a, b) => a >= b
};

const compareVersion = (version, range) => {
  const string = (range + '');
  const n = +(string.match(/\d+/) || NaN);
  const op = string.match(/^[<>]=?|/)[0];
  return comparator[op] ? comparator[op](version, n) : (version == n || n !== n);
};

const ie = range => {
  const match = userAgent.match(/(?:msie |trident.+?; rv:)(\d+)/);
  return match !== null && compareVersion(match[1], range);
};

const edge = range => {
  const match = userAgent.match(/edge\/(\d+)/);
  return match !== null && compareVersion(match[1], range);
};

const firefox = range => {
  const match = userAgent.match(/(?:firefox|fxios)\/(\d+)/);
  return match !== null && compareVersion(match[1], range);
};

const opera = range => {
  const match = userAgent.match(/(?:^opera.+?version|opr)\/(\d+)/);
  return match !== null && compareVersion(match[1], range);
};

const chrome = range => {
  const match = /google inc/.test(vendor) ? userAgent.match(/(?:chrome|crios)\/(\d+)/) : null;
  return match !== null && !opera() && compareVersion(match[1], range);
};

const safari = range => {
  const match = userAgent.match(/version\/(\d+).+?safari/);
  return match !== null && compareVersion(match[1], range);
};

const is = {
  ie,
  edge,
  firefox,
  opera,
  chrome,
  safari
};

export default is;
export {
  ie as isIe,
  edge as isEdge,
  firefox as isFirefox,
  opera as isOpera,
  chrome as isChrome,
  safari as isSafari,
}