url处理

const getUrl = key => {
  let result = null;
  const url = window.location.href.split(`?`);
  if (url.length > 1) {
    url[1].split(`&`).map(item => {
      const res = item.split(`=`);
      if (res[0] === key) {
        result = res[1];
      }
    });
  }
  return result;
};