fixup the Either monad a bit for type safetyp

1 files changed, 7 insertions, 6 deletions

diff --git a/u/process/argv.ts b/u/process/argv.ts
index 657c9a7..7190531 100644
--- a/u/process/argv.ts
+++ b/u/process/argv.ts
@@ -37,14 +37,15 @@ export const argv = <K extends string, V extends string>(
     .map((arg) => [arg, getArg(arg, argv)] as [K, IEither<Error, V>])
     .map(([arg, specified]): [K, IEither<Error, V>] => [
       arg,
-      specified.fold((e, val) => {
-        const hasDefaultVal = e && defaultArgs && arg in defaultArgs;
+      specified.fold(({ isLeft, isRight, value}): IEither<Error, V> => {
+          if (isRight) {
+              return Either.right(value);
+          }
+          const hasDefaultVal = isLeft && defaultArgs && arg in defaultArgs;
         if (hasDefaultVal) {
-          return Either.right<Error, V>(defaultArgs[arg]!);
-        } else if (!val || e) {
-          return Either.left<Error, V>(e ?? new Error("unknown"));
+          return Either.right(defaultArgs[arg]!);
         }
-        return Either.right<Error, V>(val);
+        return Either.left(value);
       }),
     ])
     .reduce(