Token_10.js

...
} else if(event.message.text === 'revoke') {
    let token = await admin.database().ref('token').child(event.source.userId).once('value');
    
    // 11. Initialize LINE Header
    // 12. Remove Access Token from RTDB
    // 13. Reply result to User Chat Room
    // 14. Revoke Access Token
}
...