code: function getPage(link) {
    if (!link) return {};
  
    let result = {};
    let reg = /(<([\S]+)>)[\S\s]+\"([\w]+)\"/;
    link.split(',').forEach((item) => {
      let itemMatch = item.match(reg);
      if (itemMatch && itemMatch.length === 4) {
        let query = querystring.parse(url.parse(itemMatch[2]).query);
        result[itemMatch[3]] = parseInt(query.page) || 1;
      }
    })
  
    return result;
  }
docs: 通过头信息中的link字段，获取当前的分页信息
  @param  {String} link 头信息中的link字段
  <https://api.github.com/repositories/11551538/issues?state=all&page=4>; rel=\"next\",
  <https://api.github.com/repositories/11551538/issues?state=all&page=32>; rel=\"last\",
  <https://api.github.com/repositories/11551538/issues?state=all&page=1>; rel=\"first\",
  <https://api.github.com/repositories/11551538/issues?state=all&page=2>; rel=\"prev\"
  @return {Object}