Nowadays, while building applications with Javascript, you’d need to run different scripts on the terminal. For instance, if you are building a SPA (Single Page Application) with React with a Nodejs API, very often you would need to start the node.js server as well as your React application so you can view it on the browser.

    "client-install": "npm install --prefix client",
    "start": "node server.js",
    "server": "nodemon server.js",
    "client": "npm start --prefix client"

NB: This package.json file is the one in the server directory and not the one in the client folder.

This would require you to open multiple terminal tabs and run npm run client and
npm run server. Overtime, this can get tiring.

To save time, you can run both commands using a single script. All you need is to use a package called concurrently.

What is Concurrently?

Concurrently is an npm package that allows you to run multiple commands on your terminal concurrently.

How to use it?

To use concurrently, you need to install it via npm with the command:

npm install --save-dev concurrently

The --save-dev flag will tell npm to install it as a devDependency.

To then add it as an npm script, you will add it in your package.json file:

"script-name": concurrently "one process" "another process"

Using the example above, in order to use concurrently to start up our React application and Node server, you will need to add a script in the server’s package.json file:

    "client-install": "npm install --prefix client",
    "start": "node server.js",
    "server": "nodemon server.js",
    "client": "npm start --prefix client",
    "dev": "concurrently \"npm run server\" \"npm run client\""

Now when you run npm run dev in the terminal, it will start both the React app and Node server for you.

For more information, check out the official docs.