Simple auth api (no db)

src/types/typeUtils.ts

@@ -0,0 +1,11 @@
+export type StringMap<T> = {
+  [key: string]: T;
+};
+
+export function narrow<T>(s: T, defd: T, ...allowed: T[]): T {
+    if (allowed.includes(s) || s == defd) {
+        return s;
+    } else {
+        return defd;
+    }
+}