Stub React Component

A fast way to generate a new component with tests anywhere in your app.

Why?

I realized that my love for tests and tools was slowing me down lately when creating new components. I would always wonder how I should do it, what should I test, and so on. And I almost always ended in the same place. Asynchronous actions, state, ui. This tool generates a couple React components and the tests that comes with (using react-testing-library). Generate a new component, and modify the files to fit you use case.

Quick Overview

# if you don't already have an app
npx create-react-app my-app
cd my-app

npx stub-react-component src/MyNewComponent

Modify src/App.jsx:

import React from 'react'
import './App.css'
import MyNewComponent from './MyNewComponent/Page'              // <-- add this

const App = () => (
  <div className="App">
    <header className="App-header">
      <h1 className="App-title">React Architecture Demo</h1>
    </header>
    <MyNewComponent />                                         {/* <-- and this */}
  </div>
)

export default App

Then run yarn start, head off to http://localhost:3000 to view the created component.

What is included in the stub component:

fetch initial products from a fake api
display a list of products
a button to display the detail of a product (fetch from the fake api)
filter the products by name
button to display a form and create a new product (backed by the fake api)

TDD Workflow

That's how these stubs can be used when working on a new feature.

first, if a real API client is available, write tests against this client
test-drive the fake-api by running the same set of tests that were written for the real client. Running the same tests is very powerful as it ensures that the fake has the same behaviour as the real client.
update the Page.test.jsx by adding a generic scenario for the new feature and use it to drive the implementation of Page.jsx.
implement, tests-first, the functionalities at a lower level by adding tests to Products.test.jsx. use it to drive the implementations of ProductsData.jsx and ProductsUi.jsx.
change the USE_FAKE_DATA constant to false in Page.jsx and verify that everything works as expected in the browser.
add style to products.css and class names to ProductsUi.jsx.
rename the files as needed. Lean on Eslint to make sure that all paths to the components are resolved.

Generated template

When running npx stub-react-component src/Example, the following files will be generated in src/Example:

Component

AsyncContent.jsx

A component that triggers and handles an AsyncFn and then render its children using a render props. Customize with your desired loading and errors state. Or remove it.

Page.jsx

Create the component by linking the asynchronous callbacks with the components.

Products.jsx

Link the data container with the UI. You shouldn't have to change it, but feel free to.

ProductsData.jsx

Owns and manage all the state of the component. Modify it to integrate all the state management that fits your needs.

ProductsUi.jsx

Render the UI as a functional component. It gets all the data and handlers needed from the <ProductsData/>. It is one big component, but it is a good thing to break it down into smaller components to make it more maintainable.

custom-prop-types.js

Define your custom types here if you are into it. Import and reuse them anywhere.

products.css

Write your styles in here, it is imported by the <Page/>. I like my css-out-of-js.

utils.js

Contains the AsyncFn utility, but again, delete it or add your own.

Tests

mocks/fake-api.js

Return some stubbed data that will be used in your component and in Page.test.jsx. Modify it so that it returns the same shape of data as your API. Ideally, it should the same data you get from the real API, so you could test this fake api and the real api with the same tests.

tests/AsyncContent.test.jsx

Test for the <AsyncContent/> component. Delete it if you use another component to handle initial loading of data.

tests/Page.test.jsx

Test the <Page/> with a generic scenario using the fake-api. Useful to make sure that the <Page/> component is built using the proper asynchronous callbacks . You could ever run the same test against your real api if it returns the same data as the fake one.

tests/Products.test.jsx

Lower level tests that don't rely on the initial data fetching. Each test is more focused on one functionality of the component.

tests/utils.test.jsx

Test the AsyncFn utility. Delete it if you are not using it.

Check out the template in src/Template. There are comments and info in each of them.