Welcome to the project!
Below you will find some information on how to perform common tasks.
- Monorepo starter
- Table of Contents
- Folder Structure
- Available Scripts
installyarn start:webappyarn build:webappyarn build:dep:webappyarn test:webappyarn release:webappyarn start:webapp-reduxyarn build:webapp-reduxyarn build:dep:webapp-reduxyarn test:webapp-reduxyarn release:webapp-reduxyarn start:commonyarn build:commonyarn build:dep:commonyarn test:commonyarn release:commonyarn cleanyarn clean:installyarn buildyarn testyarn test:watchyarn test:ciyarn lintyarn releaseyarn ncu
- Generate changelog
- Installing a Dependency
- Updating Dependencies
- Importing a Component
- Styling with Emotion
- Adding Custom Environment Variables
- Using HTTPS in Development
- Running Tests
- Developing Components in Isolation
- Troubleshooting
- How to fix it
- Usefull VSCode extensions
This monorepo is structured as follows
monorepo/
README.md
node_modules/
package.json
packages/
webapp/
node_modules/
package.json
...
common/
node_modules/
package.json
...
[...configFiles]
You may create new workspaces inside packages. Depending on being a new app or a new lib, it has its specific subfolder. Each folder with a package.json file will be a new workspace.
In the project directory, you can run:
Run
yarnto install the projects dependencies, and the dependencies within the different workspaces. You can run also
yarn `command`which will do whatever command does, and must be defined on scripts section in package.json
Runs the Main web application in the development mode. Open http://localhost:3000 to view it in the browser.
The page will reload if you make edits. You will also see any lint errors in the console.
Generates the build folder of the compiled files for Main web application The build is minified and the filenames include the hashes. Your app is ready to be deployed!
Same as yarn build:webapp but it moves the files to the root directory.
Launches the test runner for the Main web application. See the section about running tests for more information.
It launches a release for Webapp application. If there is any commit since the last release starting with:
fixwill do a patch bumpfeatwill do a minor bump!will do a major bump.
Runs the Redux web application in the development mode. Open http://localhost:3000 to view it in the browser.
The page will reload if you make edits. You will also see any lint errors in the console.
Generates the build folder of the compiled files for Redux web application The build is minified and the filenames include the hashes. Your app is ready to be deployed!
Same as yarn build:webapp-redux but it moves the files to the root directory.
Launches the test runner for the Redux web application. See the section about running tests for more information.
It launches a release for Webapp Redux application.
fixwill do a patch bumpfeatwill do a minor bump!will do a major bump.
Runs the Common components library in the development mode. Open http://localhost:9000 to view it in the browser.
The page will reload if you make edits. You will also see any lint errors in the console.
Generates the build folder of the compiled files for Common components library The build is minified and the filenames include the hashes. It will generate a static folder that can be deployed anywhere.
Same as yarn build:common but it moves the files to the root directory.
Launches the test runner for the Common components library. See the section about running tests for more information.
It launches a release for Common library.
fixwill do a patch bumpfeatwill do a minor bump!will do a major bump.
Removes dist folder.
Removes node_modules folder and executes installation command.
Generates builds for Common components library and Main web application
Launches the test runner for entire monorepo. See the section about running tests for more information.
Launches the test runner in interactive mode for entire ts-monorepo. See the section about running tests for more information.
Launches the test runner for entire ts-monorepo and generates the coverage folder. See the section about running tests for more information.
Launches eslint checker in the entire monorepo.
Releases an automatic version bump based on commit messages and generates the Changelog.md.
Checks the dependencies in all package.json files to see if there are updates.
To generate the changelog from the latest git tag for a given package, follow the next steps:
- Open a branch
chore/release-packageNamefrom latestmaster - Execute one of the
releasecommands (release, release:packageName)- This command will update the
CHANGELOG.mdof the given package, or allCHANGELOG.mdfiles if not package has been selected - Then an automatic commit will be created and will tag the commit with the new tag according to the version number of the package json file of the package. The package.json of the root directory will always be 1.0.0
- This command will update the
- Push the changes with the tags with
git push --follow-tags origin chore/release-packageName - Open a PR and merge the
chore/release-packageNamebranch (DO NOT SQUASH IT) intomasterbranch
You may install other dependencies with yarn. The flag -W indicates that the dependency must be installed in the package.json at root level.
yarn -W add <library-name>If you want to install a dependency in a specific workspace, then you can do:
yarn workspace <workspace_name> add <library-name>You can install globally npm-check-updates and run:
ncuthat will show the dependencies with new versions available to download.
With the following command, you will be able to upgrade versions number:
ncu -uand then
yarnThis project setup supports ES6 modules thanks to Babel.
While you can still use require() and module.exports, we encourage you to use import and export instead.
For example:
import React from 'react'
export const ButtonExample: React.FunctionComponent = () => {
...
}import React from 'react';
import { ButtonExample } from './ButtonExample'; // Import a component from another file
export const ButtonAndMore: React.FunctionComponent = () => {
<>
<ButtonExample />
...
</>;
};Be aware of the difference between default and named exports. It is a common source of mistakes.
We suggest that you stick to using default imports and exports when a module only exports a single thing (for example, a component). That’s what you get when you use export default Button and import Button from './Button'.
Named exports are useful for utility modules that export several functions. A module may have at most one default export and as many named exports as you like.
Learn more about ES6 modules:
This project setup uses Emotion for styling. This library allow us to write styles in js files and extending styles with a lot of flexibility.
import React from 'react';
import styled from '@emotion/styled';
export const Button: React.FunctionComponent = props => <StyledButton {...props} />;
const StyledButton = styled.button`
background: white;
`;import React from 'react';
import styled from '@emotion/styled';
import { Button } from './Button';
export const RedButton: React.FunctionComponent = props => <RedStyledButton {...props} />;
const RedStyledButton = styled(Button)`
background: red;
`;Your project can consume variables declared in your environment as if they were declared locally in your JS files. By
default you will have NODE_ENV defined for you, and any other environment variables starting with
REACT_APP_. These environment variables will be defined for you on process.env. For example, having an environment
variable named REACT_APP_SECRET_CODE will be exposed in your JS as process.env.REACT_APP_SECRET_CODE, in addition
to process.env.NODE_ENV.
Note: Changing any environment variables will require you to restart the development server if it is running.
These environment variables can be useful for displaying information conditionally based on where the project is deployed or consuming sensitive data that lives outside of version control.
First, you need to have environment variables defined. For example, let’s say you wanted to consume a secret defined
in the environment inside a <form>:
const MyComponent = () => (
<div>
<small>
You are running this application in <b>{process.env.NODE_ENV}</b> mode.
</small>
<form>
<input type="hidden" defaultValue={process.env.REACT_APP_SECRET_CODE} />
</form>
</div>
);During the build, process.env.REACT_APP_SECRET_CODE will be replaced with the current value of the REACT_APP_SECRET_CODE environment variable. Remember that the NODE_ENV variable will be set for you automatically.
When you load the app in the browser and inspect the <input>, you will see its value set to abcdef, and the bold text will show the environment provided when using npm start:
<div>
<small>You are running this application in <b>development</b> mode.</small>
<form>
<input type="hidden" value="abcdef" />
</form>
</div>Having access to the NODE_ENV is also useful for performing actions conditionally:
if (process.env.NODE_ENV !== 'production') {
analytics.disable();
}The above form is looking for a variable called REACT_APP_SECRET_CODE from the environment. In order to consume this
value, we need to have it defined in the environment. This can be done using two ways: either in your shell or in a .env file.
Defining environment variables can vary between OSes. It's also important to know that this manner is temporary for the life of the shell session.
set REACT_APP_SECRET_CODE=abcdef&&npm start(Note: the lack of whitespace is intentional.)
REACT_APP_SECRET_CODE=abcdef npm startTo define permanent environment variables, create a file called .env in the root of your project:
REACT_APP_SECRET_CODE=abcdef
These variables will act as the defaults if the machine does not explicitly set them. Please refer to the dotenv documentation for more details.
Note: If you are defining environment variables for development, your CI and/or hosting platform will most likely need these defined as well. Consult their documentation how to do this. For example, see the documentation for Travis CI or Heroku.
For each Create React App bootstrapped application you will need to set a port number in the .env file which is ignored from .gitignore, so you must create one per project like
PORT=XXXXX
# more environment variables
being the port number different if you want to start multiple applications at the same time in local development mode.
You may require the dev server to serve pages over HTTPS. One particular case where this could be useful is when using the "proxy" feature to proxy requests to an API server when that API server is itself serving HTTPS.
To do this, set the HTTPS environment variable to true, then start the dev server as usual with npm start:
set HTTPS=true&&npm start(Note: the lack of whitespace is intentional.)
HTTPS=true npm startNote that the server will use a self-signed certificate, so your web browser will almost definitely display a warning upon accessing the page.
Create React App uses Jest as its test runner.
Jest is a Node-based runner. This means that the tests always run in a Node environment and not in a real browser. This lets us enable fast iteration speed and prevent flakiness.
While Jest provides browser globals such as window thanks to jsdom, they are only approximations of the real browser behavior. Jest is intended to be used for unit tests of your logic and your components rather than the DOM quirks.
Jest will look for test files with any of the following popular naming conventions:
- Files with
.jssuffix in__tests__folders. - Files with
.test.jssuffix. - Files with
.spec.jssuffix.
The .test.js / .spec.js files (or the __tests__ folders) can be located at any depth under the src top level folder in every package.
We recommend to put the test files next to the code they are testing so that relative imports appear shorter. For example, if App.test.js and App.js are in the same folder, the test just needs to import App from './App' instead of a long relative path. Colocation also helps find tests more quickly in larger projects.
When you run yarn test:watch, Jest will launch in the watch mode. Every time you save a file, it will re-run the tests, just like yarn start recompiles the code.
The watcher includes an interactive command-line interface with the ability to run all tests, or focus on a search pattern. It is designed this way so that you can keep it open and enjoy fast re-runs. You can learn the commands from the “Watch Usage” note that the watcher prints after every run:
By default, when you run yarn test, Jest will only run the tests related to files changed since the last commit. This is an optimization designed to make your tests runs fast regardless of how many tests you have. However it assumes that you don’t often commit the code that doesn’t pass the tests.
Jest will always explicitly mention that it only ran tests related to the files changed since the last commit. You can also press a in the watch mode to force Jest to run all tests.
Jest will always run all tests on a continuous integration server or if the project is not inside a Git or Mercurial repository.
To create tests, add it() (or test()) blocks with the name of the test and its code. You may optionally wrap them in describe() blocks for logical grouping but this is neither required nor recommended.
Jest provides a built-in expect() global function for making assertions. A basic test could look like this:
import sum from './sum';
it('sums numbers', () => {
expect(sum(1, 2)).toEqual(3);
expect(sum(2, 2)).toEqual(4);
});All expect() matchers supported by Jest are extensively documented here.
You can also use jest.fn() and expect(fn).toBeCalled() to create “spies” or mock functions.
There is a broad spectrum of component testing techniques. They range from a “smoke test” verifying that a component renders without throwing, to shallow rendering and testing some of the output, to full rendering and testing component lifecycle and state changes.
Different projects choose different testing tradeoffs based on how often components change, and how much logic they contain. If you haven’t decided on a testing strategy yet, we recommend that you start with creating simple smoke tests for your components:
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
it('renders without crashing', () => {
const div = document.createElement('div');
ReactDOM.render(<App />, div);
});This test mounts a component and makes sure that it didn’t throw during rendering. Tests like this provide a lot value with very little effort so they are great as a starting point, and this is the test you will find in src/App.test.js.
When you encounter bugs caused by changing components, you will gain a deeper insight into which parts of them are worth testing in your application. This might be a good time to introduce more specific tests asserting specific expected output or behavior.
If you’d like to test components in isolation from the child components they render, we recommend using render() rendering API from Testing Library. You can write a smoke test with it too:
import { render } from '@testing-library/react';
import React from 'react';
import { Component } from './Component';
describe('Flex', () => {
it('renders component', () => {
const renderInstance = render(<Component />);
expect(renderInstance.asFragment().firstChild).toBeDefined();
});
});Unlike the previous smoke test using ReactDOM.render(), this test only renders <App> and doesn’t go deeper. For example, even if <App> itself renders a <Button> that throws, this test will pass. Shallow rendering is great for isolated unit tests, but you may still want to create some full rendering tests to ensure the components integrate correctly. Enzyme supports full rendering with mount(), and you can also use it for testing state changes and component lifecycle.
You can read the Enzyme documentation for more testing techniques. Enzyme documentation uses Chai and Sinon for assertions but you don’t have to use them because Jest provides built-in expect() and jest.fn() for spies.
Here is an example from Enzyme documentation that asserts specific output, rewritten to use Jest matchers:
import React from 'react';
import { shallow } from 'enzyme';
import App from './App';
it('renders welcome message', () => {
const wrapper = shallow(<App />);
const welcome = <h2>Welcome to React</h2>;
// expect(wrapper.contains(welcome)).to.equal(true);
expect(wrapper.contains(welcome)).toEqual(true);
});All Jest matchers are extensively documented here. Nevertheless you can use a third-party assertion library like Chai if you want to, as described below.
We recommend that you use expect() for assertions and jest.fn() for spies. If you are having issues with them please file those against Jest, and we’ll fix them. We intend to keep making them better for React, supporting, for example, pretty-printing React elements as JSX.
However, if you are used to other libraries, such as Chai and Sinon, or if you have existing code using them that you’d like to port over, you can import them normally like this:
import sinon from 'sinon';
import { expect } from 'chai';and then use them in your tests like you normally do.
We have a src/setupTests.js in each workspace. It will be automatically executed before running tests.
For example:
const localStorageMock = {
getItem: jest.fn(),
setItem: jest.fn(),
clear: jest.fn(),
};
global.localStorage = localStorageMock;You can replace it() with it.skip() to temporarily exclude a test from being executed.
Similarly, it.only() lets you focus on a specific test without running any other tests.
Jest has an integrated coverage reporter that works well with ES6 and requires no configuration.
Run yarn test:ci to include a coverage report like this:
Note that tests run much slower with coverage so it is recommended to run it separately from your normal workflow.
If you use Visual Studio Code, there is a Jest extension which works with Create React App out of the box. This provides a lot of IDE-like features while using a text editor: showing the status of a test run with potential fail messages inline, starting and stopping the watcher automatically, and offering one-click snapshot updates.
We are using Storybook to build isolated components(atoms, molecules, organisms) and its diferent states
yarn error when installing dependencies in workspace
error An unexpected error occurred: "expected workspace package to exist for \"eslint\"".
info If you think this is a bug, please open a bug report with the information provided in "/Users/user/Documents/yourcompany/monorepo-starter/packages/webapp/yarn-error.log"This is a list of recommended VSCode extensions that can help you to the development of this project:
- Bracket pair colorizer: visual hints for knowing which bracket or curly brace is the closing one
- ESLint: must for enable auto linting while developing
- Git Graph: Git Graphical integration in VSCode
- Gitlens: God
- Jest: Jest integration in VSCode to see realtime test status
- Material Icon Theme: Tons of icons for each kind of filetype
- Prettier: Another must to lint and prettify your code on file save automatically
- Vscode styled components: Syntax Highlighting for CSS in JS files