fix: allow number arg to be optional (#194)

Author: kricsleo

src/args.ts

@@ -77,6 +77,16 @@ export function parseArgs<T extends ArgsDef = ArgsDef>(
         );
       }
     } else if (arg.type === "number") {
+      if (parsedArgsProxy[arg.name] === undefined) {
+        if (arg.required) {
+          throw new CLIError(
+            `Missing required argument: --${arg.name}`,
+            "EARG",
+          );
+        }
+        continue;
+      }
+
       const _originalValue = parsedArgsProxy[arg.name];
       parsedArgsProxy[arg.name] = Number.parseFloat(
         parsedArgsProxy[arg.name] as string,