Configure CORS in Fastify using onRequest hook

fastify-cors.js

const server = fastify();
server.addHook("onRequest", async (request, reply) => {
	reply.header("Access-Control-Allow-Origin", process.env.ALLOW_ORIGIN);
	reply.header("Access-Control-Allow-Credentials", true);
	reply.header("Access-Control-Allow-Headers", "Authorization, Origin, X-Requested-With, Content-Type, Accept, X-Slug, X-UID");
	reply.header("Access-Control-Allow-Methods", "OPTIONS, POST, PUT, PATCH, GET, DELETE");
	if (request.method === "OPTIONS") {
		reply.send();
	}
});