add `expirations` endpoint

src/index.ts

@@ -74,6 +74,20 @@ server.get<{
     ORDER BY "strike";`;
   reply.status(200).send(strikes);
 })
+server.get<{
+  Params: {underlying:string, quote_date:string},
+}>('/option_quotes/:underlying/:quote_date/expirations', async (request, reply) => {
+  const expirations = (await sql`
+    SELECT DISTINCT "expiration"
+    FROM "option_quote" 
+    WHERE 
+      "underlying" = ${request.params.underlying} 
+      AND 
+      "quote_date" = ${request.params.quote_date}
+    ORDER BY "expiration";`
+  ).map(x=>x.expiration);
+  reply.status(200).send(expirations);
+})
 
 server.listen({ port: 8234, host: '127.0.0.1' }, (err, address) => {
   if (err) {