server.js

require('dotenv').config({ path: '.env' });

const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const Chatkit = require('@pusher/chatkit-server');

const app = express();

const chatkit = new Chatkit.default({
    instanceLocator: process.env.CHATKIT_INSTANCE_LOCATOR,
    key: process.env.CHATKIT_SECRET_KEY,
});

var corsOptions = {
    origin: '*'
}

app.use(cors(corsOptions));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

app.post('/delete', (req, res) => {

    const userId = req.body.userId;

    // console.log(userId);

    chatkit
        .asyncDeleteUser({
            userId: userId
        })
        .then(() => {
            chatkit.getUser({
                    userId: userId,
                })
                .then(user => {
                    console.error("User was not deleted!");
                    // console.log('got a user', user);
                })
                .catch(err => {
                    if (err.error === 'services/chatkit/not_found/user_not_found') {
                        console.log("User deleted successfully");
                        res.sendStatus(200);
                    } else {
                        res.status.apply(err.status).json(err);
                    }
                });
        })
        .catch(err => {
            console.error(err);
        });
});

app.post('/users', (req, res) => {

    const { userId } = req.body;

    chatkit
        .createUser({
            id: userId,
            name: userId,
        })
        .then(() => {
            res.sendStatus(201);
        })
        .catch(err => {
            if (err.error === 'services/chatkit/user_already_exists') {
                // console.log(`User already exists: ${userId}`);
                res.sendStatus(200);
            } else {
                res.status(err.status).json(err);
            }
        });
});

app.post('/authenticate', (req, res) => {
    const authData = chatkit.authenticate({
        userId: req.query.user_id,
    });
    res.status(authData.status).send(authData.body);
});

app.set('port', process.env.PORT || 5200);
const server = app.listen(app.get('port'), () => {
    console.log(`Express running → PORT ${server.address().port}`);
});