A mock WebStorage class for mocking localStorage and sessionStorage objects in tests.
npm install mock-webstorage   
This module exports a class implementing the Storage
interface. No
persistence strategy is built-in. This class is suitable for use as a
localStorage or sessionStorage mock in unit tests.
To access or set data on the storage instance, you must use the getItem andsetItem methods. The ability to access arbitrary properties on the native
localStorage object is not supported by this class.
If you had a file "fileToTest.js" which expected localStorage to be present
as a global, then you could test it in nodejs like this:
``js
var assert = require('assert');
var MockWebStorage = require('mock-webstorage');
global.localStorage = new MockWebStorage();
require('./fileToTest');
assert.strictEqual(localStorage.getItem('foo'), 'bar');
``
Both TypeScript and
Flow type definitions for this module are included!
The type definitions won't require any configuration to use.