serverless-token.js

const client = stream.connect(key, secret);

module.exports.token = (event, context, callback) => {
	const data = JSON.parse(event.body);

	const token = client.createUserSessionToken(data.user);

	const response = {
		statusCode: 200,
		headers: {
			'Access-Control-Allow-Origin': '*',
			'Access-Control-Allow-Credentials': true
		},
		body: JSON.stringify({ token: token })
	};

	callback(null, response);
};