fix: code repetition per code review

Author: Eomm

doc/api/util.md

@@ -1033,7 +1033,7 @@ added:
 changes:
   - version: REPLACEME
     pr-url: https://github.com/nodejs/node/pull/44631
-    description: add support for default values in input `config`.
+    description: Add support for default values in input `config`.
   - version:
     - v18.7.0
     - v16.17.0

lib/internal/util/parse_args/parse_args.js

@@ -333,15 +333,17 @@ const parseArgs = (config = kEmptyObject) => {
 
       const defaultValue = objectGetOwn(optionConfig, 'default');
       if (defaultValue !== undefined) {
-        if (optionType === 'string' && !multipleOption) {
-          validateString(defaultValue, `options.${longOption}.default`);
-        } else if (optionType === 'string' && multipleOption) {
-          validateStringArray(defaultValue, `options.${longOption}.default`);
-        } else if (optionType === 'boolean' && !multipleOption) {
-          validateBoolean(defaultValue, `options.${longOption}.default`);
-        } else if (optionType === 'boolean' && multipleOption) {
-          validateBooleanArray(defaultValue, `options.${longOption}.default`);
+        let validator;
+        switch (optionType) {
+          case 'string':
+            validator = multipleOption ? validateStringArray : validateString;
+            break;
+
+          case 'boolean':
+            validator = multipleOption ? validateBooleanArray : validateBoolean;
+            break;
         }
+        validator(defaultValue, `options.${longOption}.default`);
       }
     }
   );