js2ts: util.ts 분리

hwe/ts/util/unwrap_err.ts

@@ -0,0 +1,10 @@
+import { Nullable } from "./Nullable";
+
+type ErrType<T> = { new(msg?: string): T }
+
+export function unwrap_err<T, ErrT extends Error>(result: Nullable<T>, errType: ErrType<ErrT>, errMsg?: string): T {
+    if (result === null || result === undefined) {
+        throw new errType(errMsg);
+    }
+    return result;
+}