Storybook LocalStorage Addon

A Storybook addon and decorator for mocking and displaying current values of the window.localStorage in a Storybook panel

If you want to setup parameters to be strongly typed, see @alexgorbatchev/storybook-parameters.

Install

npm i --save-dev @alexgorbatchev/storybook-addon-localstorage

Register the addon in .storybook/main.ts

export default {
  stories: ['../stories/**/*.stories.tsx'],
  addons: ['@alexgorbatchev/storybook-addon-localstorage'],
};

Important

• If parameters.localStorage is set, localStorage.clear() will be called before populating the values.
• The values passed into parameters.localStorage must be strings because localStorage only works with strings. You can use JSON.stringify or there's a helper function provided by the addon called localStorageForStorybook.
• Finally, it's important to note that the addon works by polling and diffing mocked values in localStorage every 100ms.

Usage

Given a simple component:

export const Header = () => {
  const [user, setUser, { removeItem }] = useLocalStorage<{ name: string }>('user');

  return (
    <div>
      {user ? (
        <div>
          <div>{`Logged in as ${user.name}`}</div>
          <Button size="small" label="Log out" onClick={() => removeItem()} />
        </div>
      ) : (
        <div>
          <div>No one is signed in</div>
          <Button size="small" label="Log in" onClick={() => setUser({ name: 'John' })} />
        </div>
      )}
    </div>
  );
};

You can write a story as

import { localStorageForStorybook } from '@alexgorbatchev/storybook-addon-localstorage';
import { Meta, StoryObj } from '@storybook/react';

import { Header } from './Header';

const meta: Meta<typeof Header> = {
  title: 'Example/Header',
  component: Header,
};

export default meta;

type Story = StoryObj<typeof Header>;

export const JohnLoggedIn: Story = {
  parameters: {
    // this helper automatically stringifies the values using `JSON.stringify`
    localStorage: localStorageForStorybook({
      value: 123,
      user: { name: 'John' },
    }),
  },
};

export const JaneLoggedIn: Story = {
  parameters: {
    // if you have own serializer, you can use it as well
    localStorage: {
      value: '123',
      user: JSON.stringify({ name: 'Jane' }),
    },
  },
};

Strongly typed example:

import { Meta, StoryObj } from '@alexgorbatchev/storybook-parameters';
import { LocalStorageParameters } from '@alexgorbatchev/storybook-addon-localstorage';

interface StoryParameters extends LocalStorageParameters {}

const meta: Meta<typeof Header, StoryParameters> = {
  title: 'Header',
  component: Header,
};

export default meta;

type Story = StoryObj<typeof Header, StoryParameters>;

export const JohnLoggedIn: Story = {
  parameters: {
    // `localStorage` will show up in `Parameters`
    localStorage: {
      key: 'value',
    },
  },
};

Development Scripts

• npm run storybook starts Storybook
• npm test runs tests
• npm run test:watch runs tests in watch mode
• tsup build ./dist