This simple Node.js script (app.js) demonstrates how to generate a JSON Web Token (JWT) using the jsonwebtoken library. This token can be used for various authentication and authorization purposes in web applications.

1. Install Dependencies: Make sure you have Node.js installed on your machine. If not, you can download it from nodejs.org. Then, install the required jsonwebtoken library by running:

   $ npm i jsonwebtoken
   

2. Replace Placeholder: In the app.js file, replace the 'SECRETKEY' with your actual secret key. This key is used to sign the JWT and should be kept secure.

3. Run the Script: Execute the script by running:

   $ node app.js
   

4. Generated Token: The script will output the generated JWT token to the console.

   $ Generated JWT token: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpYXQiOjE2NDc3MjM3OTIsImV4cCI6MTY0NzcyNzQ5Mn0.b_5x19Z-1mKhWi7H8x4bS8sx8VfTW0HXhbI5u7yVtIg
   

• app.js: Node.js script for generating JWT token.
• README.md: This file containing instructions and information about the script.

• jsonwebtoken: Library for generating JSON Web Tokens.

$ node app.js
Generated JWT token: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpYXQiOjE2NDc3MjM3OTIsImV4cCI6MTY0NzcyNzQ5Mn0.b_5x19Z-1mKhWi7H8x4bS8sx8VfTW0HXhbI5u7yVtIg