如何处理jest测试中的localStorage？

Question

我总是在Jest测试中得到“localstorage is not defined”，这很有意义，但我有什么选择呢？撞上砖墙。

Answer 1

我通过以下内容找到了答案:https://groups.google.com/forum/#！topic/jestjs/9ephunwvytg

设置包含以下内容的文件：

var localStorageMock = (function() {
  var store = {};
  return {
    getItem: function(key) {
      return store[key];
    },
    setItem: function(key, value) {
      store[key] = value.toString();
    },
    clear: function() {
      store = {};
    },
    removeItem: function(key) {
      delete store[key];
    }
  };
})();
Object.defineProperty(window, 'localStorage', { value: localStorageMock });

然后在Jest配置下将以下行添加到package.json中

“SetupTestFrameworkScriptFile”：“PATH_TO_YOUR_FILE”,

Answer 2

来自@Chiedo的伟大解决方案

不过，我们使用的是ES2015语法，我觉得这样写会稍微干净一些。

class LocalStorageMock {
  constructor() {
    this.store = {};
  }

  clear() {
    this.store = {};
  }

  getItem(key) {
    return this.store[key] || null;
  }

  setItem(key, value) {
    this.store[key] = String(value);
  }

  removeItem(key) {
    delete this.store[key];
  }
};

global.localStorage = new LocalStorageMock;