// port and request handler as arguments
const centralSystem = new CentralSystem(3000, (req, { chargePointId }) => {
  switch (req.action) {
    case 'Heartbeat':
      // returns a successful response
      // (we pass the action and ocpp version so typescript knows which fields are needed)
      return {
        action: req.action,
        ocppVersion: req.ocppVersion,
        currentTime: new Date().toISOString()
      };
  }
  throw new Error('message not supported');
});

// Returns a Either(Error or Success) object(functional, will not throw on error)
const response = await centralSystem.sendRequest({ chargePointId: '123', ocppVersion: 'v1.6-json', action: 'GetConfiguration', payload: {} });
// it can be used in a functional way
response.map(({ configurationKey }) => configurationKey[0].key);
// or can be used in the standard JS way(will throw if there was an error)
const unsafeResponse = response.unsafeCoerce();

// port, request handler and central system URL as arguments
const chargepoint = new ChargePoint(3001, req => {
  switch (action) {
    case 'GetConfiguration':
      // returns a successful response
      // (we pass the action and ocpp version so typescript knows which fields are needed)
      return {
        action: req.action,
        ocppVersion: req.ocppVersion,
        configurationKey: [],
      };
  }
  throw new Error('message not supported');
});

const response = await chargepoint.sendRequest({ action: 'Heartbeat', ocppVersion: '1.6-json', payload: {} );