Add time_and_date plugin. Use it for timezones and date formats around the bot.

backend/src/utils/tValidTimezone.ts

@@ -0,0 +1,13 @@
+import * as t from "io-ts";
+import { either } from "fp-ts/lib/Either";
+import { isValidTimezone } from "./isValidTimezone";
+
+export const tValidTimezone = new t.Type<string, string>(
+  "tValidTimezone",
+  (s): s is string => typeof s === "string",
+  (from, to) =>
+    either.chain(t.string.validate(from, to), input => {
+      return isValidTimezone(input) ? t.success(input) : t.failure(from, to, `Invalid timezone: ${input}`);
+    }),
+  s => s,
+);