.gitignore

.env.sh
node_modules
package-lock.json

index.js

import {clientCredentialsGrant, discovery} from 'openid-client'

(async () => {
  const config = await discovery({
    server: new URL(process.env.SERVER_ORIGIN),
    clientId: process.env.CLIENT_ID,
    clientSecret: process.env.CLIENT_SECRET,
  })
  const tokens = await clientCredentialsGrant(
    config,
    {},
  )

  console.log('Token Endpoint Response', tokens)
})()

package.json

{
  "name": "oauth2_client_credentials_test",
  "type": "module",
  "private": true,
  "license": "MIT",
  "author": "mryhryki",
  "scripts": {
    "start": "source ./.env.sh && node ./index.js"
  },
  "dependencies": {
    "openid-client": "^6.8.1"
  }
}