1. I added a .env file to save the Stack Overflow client id, client secret.
2. dded .gitignore to prevent pushing this file.
3. Added the other OAuth providers to .gitignore to keep the GitHub repo as a MCVE.
4. Edited the README.md

Documentation: https://api.stackexchange.com/docs/authentication.

1. Register an OAuth app authentication client on https://stackapps.com.
2. From the above listing geth the client id, client secret and key.
   • Stack Overflow / Stack Exchange API requests optionally can include a key to get higher requests quotas.
   • I added this key to the .env file, but this is not compulsory.
3. You might want to make a copy of the examples directory of https://github.com/lelylan/simple-oauth2
4. Look at the included files for OAuth providers, choose one, make a copy and adapt it.
   • I called the file stackoverflow.js
5. Edit package.json to add a script command for your the Stack Overflow file.

6. If you haven't edited the catch clause, It's very likely that you will get Access Token Error The content-type is not JSON compatible mesasge in the terminal.

As a workadound I added the new directory with two files. The directory name is stackoverflow-fetchand the file names are index.js and authentication.js. I used Node.js fetch instead of getToken method from simple-oauth2. Requires Node.js version 18 or greater.

Below is the content from the simple-oauth2's example directory

Before running any example, please set the following environment variables:

export CLIENT_ID="your client id"
export CLIENT_SECRET="your client secret"

The following authorization services are provided as examples to get a better idea of how to use this library on some of the most common use cases:

Microsoft requires the credentials information during the token exchange to be sent at the request body. It also requires to send the redirect_uri argument. See the ./microsoft.js module as a reference implementation or execute the example with:

npm run start:microsoft

See the ./github.js module as a reference implementation or execute the example with:

npm run start:github

See the ./dropbox.js module as a reference implementation or execute the example with:

npm run start:dropbox