Created
October 31, 2019 13:43
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| import invariant from 'invariant' | |
| import warning from 'warning' | |
| function identity(state) { | |
| return state | |
| } | |
| function parse(serializedJSON) { | |
| if (serializedJSON) { | |
| try { | |
| return JSON.parse(serializedJSON) | |
| } catch (e) { | |
| warning(false, 'Could not parse stored item.') | |
| } | |
| } | |
| return null | |
| } | |
| function load({ name, upgrader, version }) { | |
| return () => { | |
| const previousStorage = parse(localStorage.getItem(name)) | |
| if (previousStorage) { | |
| return previousStorage.version < version | |
| ? upgrader(previousStorage.data, previousStorage.version) | |
| : previousStorage.data | |
| } | |
| return null | |
| } | |
| } | |
| function save({ name, version }) { | |
| return data => { | |
| localStorage.setItem(name, JSON.stringify({ version, data })) | |
| } | |
| } | |
| function clear({ name }) { | |
| return () => { | |
| localStorage.removeItem(name) | |
| } | |
| } | |
| function open(name, version, upgrader = identity) { | |
| invariant(name, 'A storage name is required.') | |
| invariant(version != null, 'A storage version is required.') | |
| const context = { name, version, upgrader } | |
| return { | |
| load: load(context), | |
| save: save(context), | |
| clear: clear(context), | |
| } | |
| } | |
| function clearAll() { | |
| localStorage.clear() | |
| } | |
| export default { open, clearAll } |
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| import Storages from './Storages' | |
| const storageName = 'name' | |
| const data = { a: 0, b: 1 } | |
| const upgradedData = { c: 2, d: 3 } | |
| function resetLocalStorage() { | |
| localStorage.clear() | |
| console.error.mockReset() | |
| } | |
| describe('Storages', () => { | |
| beforeEach(resetLocalStorage) | |
| afterAll(resetLocalStorage) | |
| it('should return null when there are no stored data', () => { | |
| expect(Storages.open(storageName, 1).load()).toBeNull() | |
| }) | |
| it('should save data by name', () => { | |
| Storages.open(storageName, 2).save(data) | |
| expect(localStorage.getItem(storageName)).toBeDefined() | |
| }) | |
| it('should load data by name', () => { | |
| const storage = Storages.open(storageName, 1) | |
| storage.save(data) | |
| expect(storage.load()).toEqual(data) | |
| }) | |
| it('should upgrade the data', () => { | |
| Storages.open(storageName, 1).save(data) | |
| const upgrader = jest.fn(() => upgradedData) | |
| const loadedData = Storages.open(storageName, 3, upgrader).load() | |
| expect(upgrader).toHaveBeenCalledWith(data, 1) | |
| expect(loadedData).toEqual(upgradedData) | |
| }) | |
| it('should not upgrade the data by default', () => { | |
| Storages.open(storageName, 1).save(data) | |
| const loadedData = Storages.open(storageName, 3).load() | |
| expect(loadedData).toEqual(data) | |
| }) | |
| it('should not invoke the upgrader for same versions', () => { | |
| Storages.open(storageName, 1).save(data) | |
| const upgrader = jest.fn() | |
| const loadedData = Storages.open(storageName, 1, upgrader).load() | |
| expect(upgrader).not.toHaveBeenCalled() | |
| expect(loadedData).toEqual(data) | |
| }) | |
| it('should clear a storage', () => { | |
| const storage = Storages.open(storageName, 1) | |
| storage.save(data) | |
| storage.clear() | |
| expect(storage.load()).toBeNull() | |
| expect(localStorage.getItem(storageName)).toBeNull() | |
| }) | |
| it('should support multiple storages at the same time', () => { | |
| const storage1 = Storages.open(storageName, 1) | |
| const storage2 = Storages.open('name-2', 1) | |
| storage1.save(data) | |
| storage2.save(upgradedData) | |
| expect(storage2.load()).toEqual(upgradedData) | |
| expect(storage1.load()).toEqual(data) | |
| storage1.clear() | |
| expect(storage2.load()).toEqual(upgradedData) | |
| expect(storage1.load()).toBeNull() | |
| }) | |
| it('should clear all storages', () => { | |
| const storage1 = Storages.open(storageName, 1) | |
| const storage2 = Storages.open('name-2', 1) | |
| storage1.save(data) | |
| storage2.save(upgradedData) | |
| Storages.clearAll() | |
| expect(storage1.load()).toBeNull() | |
| expect(storage2.load()).toBeNull() | |
| }) | |
| it('should return null for a corrupted storage', () => { | |
| localStorage.setItem(storageName, "I'm not JSON") | |
| expect(Storages.open(storageName, 1).load()).toBeNull() | |
| expect(console.error).toHaveBeenCalledTimes(1) | |
| }) | |
| it('should throw if a name is not specified', () => { | |
| expect(() => Storages.open()).toThrow() | |
| }) | |
| it('should throw if a version is not specified', () => { | |
| expect(() => Storages.open(storageName)).toThrow() | |
| }) | |
| }) |
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