Update README

* Include node version
* Add mock reset test example
* prettier

README.md

@@ -1,13 +1,22 @@
+Use this module with [Jest](https://facebook.github.io/jest/) to run web tests
+that rely on `localstorage` and / or `sessionStorage` where you want a working
+localStorage API with mocked functions.
 
-Use this module with [Jest](https://facebook.github.io/jest/) to run web tests that rely on `localstorage` and / or `sessionStorage` where you want a working localStorage API with mocked functions.
+This module has no runtime dependencies so your project won't pull in additional
+module dependencies by using this.
 
-This module has no runtime dependencies so your project won't pull in additional module dependencies by using this.
-
-[![npm](https://img.shields.io/npm/v/jest-localstorage-mock.svg)](https://www.npmjs.com/package/jest-localstorage-mock) [![npm](https://img.shields.io/npm/l/jest-localstorage-mock.svg)](https://github.com/clarkbw/jest-localstorage-mock/blob/master/LICENSE) [![Codecov](https://img.shields.io/codecov/c/github/clarkbw/jest-localstorage-mock.svg)](https://codecov.io/gh/clarkbw/jest-localstorage-mock) [![Greenkeeper badge](https://badges.greenkeeper.io/clarkbw/jest-localstorage-mock.svg)](https://greenkeeper.io/) [![Twitter](https://img.shields.io/twitter/url/https/github.com/clarkbw/jest-localstorage-mock.svg?style=social)](https://twitter.com/intent/tweet?text=Wow:&url=%5Bobject%20Object%5D)
+[![npm](https://img.shields.io/npm/v/jest-localstorage-mock.svg)](https://www.npmjs.com/package/jest-localstorage-mock)
+[![npm](https://img.shields.io/npm/l/jest-localstorage-mock.svg)](https://github.com/clarkbw/jest-localstorage-mock/blob/master/LICENSE)
+[![Codecov](https://img.shields.io/codecov/c/github/clarkbw/jest-localstorage-mock.svg)](https://codecov.io/gh/clarkbw/jest-localstorage-mock)
+[![Greenkeeper badge](https://badges.greenkeeper.io/clarkbw/jest-localstorage-mock.svg)](https://greenkeeper.io/)
+[![Twitter](https://img.shields.io/twitter/url/https/github.com/clarkbw/jest-localstorage-mock.svg?style=social)](https://twitter.com/intent/tweet?text=Wow:&url=%5Bobject%20Object%5D)
 
 ## Install
 
-This should only be installed as a development dependency (`devDependencies`) as it is only designed for testing.
+This should only be installed as a development dependency (`devDependencies`) as
+it is only designed for testing. The module is transpiled via
+[babel](https://github.com/babel/babel) to support the current active Node LTS
+version (6.11.3).
 
 yarn:
 
@@ -23,39 +32,44 @@ npm i --save-dev jest-localstorage-mock
 
 ## Setup
 
-The simplest setup is to use the module system, you may also choose to create a setup file.
+The simplest setup is to use the [module](#module) system, you may also choose
+to create a [setup file](#setup-file) if needed.
 
 ### Module
 
-In your `package.json` under the `jest` [configuration section](https://facebook.github.io/jest/docs/en/configuration.html#content) create a `setupFiles` array and add `jest-localstorage-mock` to the array.
+In your `package.json` under the `jest`
+[configuration section](https://facebook.github.io/jest/docs/en/configuration.html#content)
+create a `setupFiles` array and add `jest-localstorage-mock` to the array.
 
 ```json
-"jest": {
-  "setupFiles": [
-    "jest-localstorage-mock"
-  ]
+{
+  "jest": {
+    "setupFiles": ["jest-localstorage-mock"]
+  }
 }
 ```
 
-If you already have a `setupFiles` attribute you can also append `jest-localstorage-mock` to the array.
+If you already have a `setupFiles` attribute you can also append
+`jest-localstorage-mock` to the array.
 
 ```json
-"jest": {
-  "setupFiles": [
-    "./__setups__/other.js",
-    "jest-localstorage-mock"
-  ]
+{
+  "jest": {
+    "setupFiles": ["./__setups__/other.js", "jest-localstorage-mock"]
+  }
 }
 ```
 
 ### Setup file
 
-Alternatively you can create a new setup file which then requires this module or add the `require` statement to an existing setup file.
+Alternatively you can create a new setup file which then requires this module or
+add the `require` statement to an existing setup file.
 
 `__setups__/localstorage.js`
+
 ```js
 import 'jest-localstorage-mock';
-// or 
+// or
 require('jest-localstorage-mock');
 ```
 
@@ -71,33 +85,43 @@ Add that file to your `setupFiles` array:
 
 ### In create-react-app
 
-For a [create-react-app](https://github.com/facebookincubator/create-react-app) project you can replace the [suggested mock](https://github.com/facebookincubator/create-react-app/tree/master/packages/react-scripts/template#srcsetuptestsjs) with this at the beginning of the existing `src/setupTests.js` file:
+For a [create-react-app](https://github.com/facebookincubator/create-react-app)
+project you can replace the
+[suggested mock](https://github.com/facebookincubator/create-react-app/tree/master/packages/react-scripts/template#srcsetuptestsjs-1)
+with this at the beginning of the existing `src/setupTests.js` file:
 
 ```js
-require("jest-localstorage-mock");
+require('jest-localstorage-mock');
 ```
 
 ## In tests
 
-By including this in your Jest setup you'll allow tests that expect a `localStorage` and `sessionStorage` object to continue to run.  The module can also allow you to use the mocks provided to check that your localStorage is being used as expected.
+By including this in your Jest setup you'll allow tests that expect a
+`localStorage` and `sessionStorage` object to continue to run. The module can
+also allow you to use the mocks provided to check that your localStorage is
+being used as expected.
 
-The `__STORE__` attribute of `localStorage.__STORE__` or `sessionStorage.__STORE__` is made available for you to directly access the storage object if needed.
+The `__STORE__` attribute of `localStorage.__STORE__` or
+`sessionStorage.__STORE__` is made available for you to directly access the
+storage object if needed.
 
 ### Test Examples
 
 Check that your `localStorage` calls were made when they were supposed to.
 
 ```js
 test('should save to localStorage', () => {
-  const KEY = 'foo', VALUE = 'bar';
+  const KEY = 'foo',
+    VALUE = 'bar';
   dispatch(action.update(KEY, VALUE));
   expect(localStorage.setItem).toHaveBeenLastCalledWith(KEY, VALUE);
   expect(localStorage.__STORE__[KEY]).toBe(VALUE);
   expect(Object.keys(localStorage.__STORE__).length).toBe(1);
 });
 ```
 
-Check that your `sessionStorage` is empty, examples work with either `localStorage` or `sessionStorage`.
+Check that your `sessionStorage` is empty, examples work with either
+`localStorage` or `sessionStorage`.
 
 ```js
 test('should have cleared the sessionStorage', () => {
@@ -112,11 +136,46 @@ Check that `localStorage` calls were not made when they shouldn't have been.
 
 ```js
 test('should not have saved to localStorage', () => {
-  const KEY = 'foo', VALUE = 'bar';
+  const KEY = 'foo',
+    VALUE = 'bar';
   dispatch(action.notIdempotent(KEY, VALUE));
   expect(localStorage.setItem).not.toHaveBeenLastCalledWith(KEY, VALUE);
   expect(Object.keys(localStorage.__STORE__).length).toBe(0);
 });
 ```
 
-See the [contributing guide](./CONTRIBUTING.md) for details on how you can contribute.
+Reset your `localStorage` data and mocks before each test to prevent leaking.
+
+```js
+beforeEach(() => {
+  // values stored in tests will also be available in other tests unless you run
+  localStorage.clear();
+  // or directly reset the storage
+  localStorage.__STORE__ = {};
+  // you may also reset all mocks, which could impact your other mocks
+  jest.resetAllMocks();
+  // or individually reset a mock used
+  localStorage.setItem.mockReset();
+});
+
+test('should not impact the next test', () => {
+  const KEY = 'foo',
+    VALUE = 'bar';
+  dispatch(action.update(KEY, VALUE));
+  expect(localStorage.setItem).toHaveBeenLastCalledWith(KEY, VALUE);
+  expect(localStorage.__STORE__[KEY]).toBe(VALUE);
+  expect(Object.keys(localStorage.__STORE__).length).toBe(1);
+});
+
+test('should not be impacted by the previous test', () => {
+  const KEY = 'baz',
+    VALUE = 'zab';
+  dispatch(action.update(KEY, VALUE));
+  expect(localStorage.setItem).toHaveBeenLastCalledWith(KEY, VALUE);
+  expect(localStorage.__STORE__[KEY]).toBe(VALUE);
+  expect(Object.keys(localStorage.__STORE__).length).toBe(1);
+});
+```
+
+See the [contributing guide](./CONTRIBUTING.md) for details on how you can
+contribute.