js2ts: util.ts 분리

hwe/ts/util/unwrap.ts

@@ -0,0 +1,9 @@
+import { Nullable } from "./Nullable";
+import { NotNullExpected } from "./NotNullExpected";
+
+export function unwrap<T>(result: Nullable<T>): T {
+    if (result === null || result === undefined) {
+        throw new NotNullExpected();
+    }
+    return result;
+}