49 lines
1.3 KiB
JavaScript
49 lines
1.3 KiB
JavaScript
/**
|
|
* Manage the instance of a custom `window.localStorage`
|
|
*
|
|
* This only encapsulates the setup / teardown logic so that it can easily be
|
|
* reused with different implementations (i.e. a spy or a [fake][1])
|
|
*
|
|
* [1]: https://stackoverflow.com/a/41434763/1708147
|
|
*
|
|
* @param {() => any} fn Function that returns the object to use for localStorage
|
|
*/
|
|
const useLocalStorage = (fn) => {
|
|
const origLocalStorage = window.localStorage;
|
|
let currentLocalStorage = origLocalStorage;
|
|
|
|
Object.defineProperty(window, 'localStorage', {
|
|
get: () => currentLocalStorage,
|
|
});
|
|
|
|
beforeEach(() => {
|
|
currentLocalStorage = fn();
|
|
});
|
|
|
|
afterEach(() => {
|
|
currentLocalStorage = origLocalStorage;
|
|
});
|
|
};
|
|
|
|
/**
|
|
* Create an object with the localStorage interface but `jest.fn()` implementations.
|
|
*/
|
|
export const createLocalStorageSpy = () => {
|
|
let storage = {};
|
|
|
|
return {
|
|
clear: jest.fn(() => {
|
|
storage = {};
|
|
}),
|
|
getItem: jest.fn((key) => (key in storage ? storage[key] : null)),
|
|
setItem: jest.fn((key, value) => {
|
|
storage[key] = value;
|
|
}),
|
|
removeItem: jest.fn((key) => delete storage[key]),
|
|
};
|
|
};
|
|
|
|
/**
|
|
* Before each test, overwrite `window.localStorage` with a spy implementation.
|
|
*/
|
|
export const useLocalStorageSpy = () => useLocalStorage(createLocalStorageSpy);
|