README.md

API

Application Programming Interface (API) allows other applications to communicate with your application
An API will make the app's functionality accessible through programmatic requests instead of being tightly coupled to a specific environment (web browser).
Add a router-api file

npm install and require jsonwebtoken
Use the sign() method of jwt w/ three (3) arguments
- 1st: object you want to store in this token
- 2nd: secret string of characters that the package will use to generate the token
- 3rd: object w/ options, like expiration date for tokens
Use verify() method of jwt w/ two (2) arguments to determine if its the valid token that the server generated
- 1st: token you want to verify, E.g. req.body.token
- 2nd: JWT secret string
JWT is popular because it allows stateless authentication, which means you don't need to track session data on the server

Cross Origin Resource Sharing (CORS), web browsers will not send off asychronous requests to other domains, unless the other domain permitted it
npm install and require cors so that users will be able to access API using other domains (like codepen)