MERN APP

Folder Structure

NOTE : This may be outdated After creation, your project should look like this:

FirstMernApp/
  README.md
  node_modules/
  package.json
  public/
    index.html
    favicon.ico
  server/
    routes/
      api/
  src/
    App.css
    App.js
    App.test.js
    index.css
    index.js
    logo.svg

For the project to build, these files must exist with exact filenames:

• public/index.html is the page template;
• src/index.js is the JavaScript entry point.

You can delete or rename the other files.

You may create subdirectories inside src. For faster rebuilds, only files inside src are processed by Webpack.
You need to put any JS and CSS files inside src, otherwise Webpack won’t see them.

Only files inside public can be used from public/index.html.
Read instructions below for using assets from JavaScript and HTML.

You can, however, create more top-level directories.
They will not be included in the production build so you can use them for things like documentation.

Available Scripts

In the project directory, you can run:

npm start

Runs the app 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.

npm test

Launches the test runner in the interactive watch mode.
See the section about running tests for more information.

npm run build

Builds the app for production to the build folder.
It correctly bundles React in production mode and optimizes the build for the best performance.

The build is minified and the filenames include the hashes.
Your app is ready to be deployed!

See the section about deployment for more information.

npm run eject

Note: this is a one-way operation. Once you eject, you can’t go back!

If you aren’t satisfied with the build tool and configuration choices, you can eject at any time. This command will remove the single build dependency from your project.

Instead, it will copy all the configuration files and the transitive dependencies (Webpack, Babel, ESLint, etc) right into your project so you have full control over them. All of the commands except eject will still work, but they will point to the copied scripts so you can tweak them. At this point you’re on your own.

You don’t have to ever use eject. The curated feature set is suitable for small and middle deployments, and you shouldn’t feel obligated to use this feature. However we understand that this tool wouldn’t be useful if you couldn’t customize it when you are ready for it.

Formatting Code Automatically

Prettier is an opinionated code formatter with support for JavaScript, CSS and JSON. With Prettier you can format the code you write automatically to ensure a code style within your project. See the Prettier's GitHub page for more information, and look at this page to see it in action.

To format our code whenever we make a commit in git, we need to install the following dependencies:

npm install --save husky lint-staged prettier

Alternatively you may use yarn:

yarn add husky lint-staged prettier

• husky makes it easy to use githooks as if they are npm scripts.
• lint-staged allows us to run scripts on staged files in git. See this blog post about lint-staged to learn more about it.
• prettier is the JavaScript formatter we will run before commits.

Now we can make sure every file is formatted correctly by adding a few lines to the package.json in the project root.

Add the following line to scripts section:

  "scripts": {
+   "precommit": "lint-staged",
    "start": "react-scripts start",
    "build": "react-scripts build",

Next we add a 'lint-staged' field to the package.json, for example:

  "dependencies": {
    // ...
  },
+ "lint-staged": {
+   "src/**/*.{js,jsx,json,css}": [
+     "prettier --single-quote --write",
+     "git add"
+   ]
+ },
  "scripts": {

Now, whenever you make a commit, Prettier will format the changed files automatically. You can also run ./node_modules/.bin/prettier --single-quote --write "src/**/*.{js,jsx,json,css}" to format your entire project for the first time.

Next you might want to integrate Prettier in your favorite editor. Read the section on Editor Integration on the Prettier GitHub page.