localStorage设置过期时间

        /**
       * 设置cookie
       * @param {[type]} key   [键名]
       * @param {[type]} value [键值]
       * @param {[type]} days  [保存的时间（天）]
       */
      setCookie: function (key, value, days) {
        // 设置过期原则
        if (!value) {
          localStorage.removeItem(key)
        } else {
          var Days = days || 7; // 默认保留7天
          var exp = new Date();
          localStorage[key] = JSON.stringify({
            value,
            expires: exp.getTime() + Days * 24 * 60 * 60 * 1000
          })
        }
      },
      getCookie: function (name) {
        try {
          let o = JSON.parse(localStorage[name])
          if (!o || o.expires < Date.now()) {
            return null
          } else {
            return o.value
          }
        } catch (e) {
            // 兼容其他localstorage 
          console.log(e)
          return localStorage[name]
        } finally {
        }
      },

参考链接
locaStorage用法