Vue开发中踩坑-Day3

Vue开发中踩坑-Day3

昨天的本地储存问题，写了一个模块，根据MDN中给的算法，是的大多情况下都可用。

function storageAvailable(type) {
  let storage;
  try {
    storage = window[type];
    let x = '__storage_test__';
    storage.setItem(x, x);
    storage.removeItem(x);
    return true;
  }
  catch(e) {
    return e instanceof DOMException && (
        // everything except Firefox
      e.code === 22 ||
      // Firefox
      e.code === 1014 ||
      // test name field too, because code might not be present
      // everything except Firefox
      e.name === 'QuotaExceededError' ||
      // Firefox
      e.name === 'NS_ERROR_DOM_QUOTA_REACHED') &&
      // acknowledge QuotaExceededError only if there's something already stored
      (storage && storage.length !== 0);
  }
}


function enableLocalStorage() {
  if (!window.localStorage) {
    let s = '__cookie_test__';
    document.cookie = s
    if(document.cookie.indexOf(s) === -1) {
      alert('cookie不可用，请启用浏览器cookie')
      return false
    }
    Object.defineProperty(window, "localStorage", new (function () {
      let aKeys = [], oStorage = {};
      Object.defineProperty(oStorage, "getItem", {
        value: function (sKey) { return sKey ? this[sKey] : null; },
        writable: false,
        configurable: false,
        enumerable: false
      });
      Object.defineProperty(oStorage, "key", {
        value: function (nKeyId) { return aKeys[nKeyId]; },
        writable: false,
        configurable: false,
        enumerable: false
      });
      Object.defineProperty(oStorage, "setItem", {
        value: function (sKey, sValue) {
          if(!sKey) { return; }
          document.cookie = escape(sKey) + "=" + escape(sValue) + "; expires=Tue, 19 Jan 2038 03:14:07 GMT; path=/";
        },
        writable: false,
        configurable: false,
        enumerable: false
      });
      Object.defineProperty(oStorage, "length", {
        get: function () { return aKeys.length; },
        configurable: false,
        enumerable: false
      });
      Object.defineProperty(oStorage, "removeItem", {
        value: function (sKey) {
          if(!sKey) { return; }
          document.cookie = escape(sKey) + "=; expires=Thu, 01 Jan 1970 00:00:00 GMT; path=/";
        },
        writable: false,
        configurable: false,
        enumerable: false
      });
      this.get = function () {
        let iThisIndx;
        for (let sKey in oStorage) {
          iThisIndx = aKeys.indexOf(sKey);
          if (iThisIndx === -1) { oStorage.setItem(sKey, oStorage[sKey]); }
          else { aKeys.splice(iThisIndx, 1); }
          delete oStorage[sKey];
        }
        for (aKeys; aKeys.length > 0; aKeys.splice(0, 1)) { oStorage.removeItem(aKeys[0]); }
        for (let aCouple, iKey, nIdx = 0, aCouples = document.cookie.split(/\s*;\s*/); nIdx < aCouples.length; nIdx++) {
          aCouple = aCouples[nIdx].split(/\s*=\s*/);
          if (aCouple.length > 1) {
            oStorage[iKey = unescape(aCouple[0])] = unescape(aCouple[1]);
            aKeys.push(iKey);
          }
        }
        return oStorage;
      };
      this.configurable = false;
      this.enumerable = true;
    })());
  }
  return true
}

if (!(storageAvailable('localStorage') || enableLocalStorage())) {
  alert('请关闭浏览器隐私模式或者启用cookie, 否则网站功能将出现异常！')
}