Emit Event to Event Grid from an Azure Function

eventgrid.js

function EmitEvent(ringEvent, context, callback) {
    context.log('Sending event to event grid.');
    var eventGridPayload = [{
        id: utils.generateUUID(),
        eventType: ringEvent['kind'],
        subject: 'ring/frontDoor',
        eventTime: new Date().toISOString(),
        data: ringEvent
    }];
    var response = '';
    var req = https.request(options, (res) => {
        res.setEncoding('utf8');
        res.on('data', (chunk) => {
            response += chunk;
        });
        res.on('end', () => {
            context.log(response);
            callback(response);
        });
    });
    req.write(JSON.stringify(eventGridPayload));
    req.end();
}