3 files changed, 92 insertions, 2 deletions
diff --git a/errhandlers/validators.go b/errhandlers/anime_validators.go
index 4e4137d..b51afa6 100644
--- a/errhandlers/validators.go
+++ b/errhandlers/anime_validators.go
@@ -33,7 +33,7 @@ func IsValidRankingType(rankingType string) bool {
   return false
 }
 
-// Checks if given rankingType is valid
+// Checks if given field is valid
 func IsValidField(field string) bool {
   switch field {
     case
diff --git a/errhandlers/errhandlers.go b/errhandlers/errhandlers.go
index 14c1d33..5f4db25 100644
--- a/errhandlers/errhandlers.go
+++ b/errhandlers/errhandlers.go
@@ -22,8 +22,9 @@ import (
   "github.com/MikunoNaka/MAL2Go/util"
 )
 
-// if fields aren't specified
+// this is only for anime fields
 func FieldsErrHandler(fields []string) ([]string, error) {
+  // if fields aren't specified
   if cap(fields) == 0 {
     // uses all the default fields if none specified
     return util.DefaultFields, nil
@@ -40,6 +41,25 @@ func FieldsErrHandler(fields []string) ([]string, error) {
   return fields, nil
 }
 
+// only for manga fields
+func MangaFieldsErrHandler(fields []string) ([]string, error) {
+  // if fields aren't specified
+  if cap(fields) == 0 {
+    // uses all the default fields if none specified
+    return util.DefaultMangaFields, nil
+  }
+
+  // checks if each given field is valid
+  for _, j := range(fields) {
+    if !IsValidMangaField(j) {
+      return []string{}, errors.New(fmt.Sprintf("InvalidFieldError: Invalid field specified: \"%s\"", j))
+    }
+  }
+
+  // everything's fine!
+  return fields, nil
+}
+
 // if limit or error specified are above the limit
 func LimitErrHandler(limit, maxLimit int) error {
   if limit > maxLimit {
diff --git a/errhandlers/manga_validators.go b/errhandlers/manga_validators.go
new file mode 100644
index 0000000..fa12e5f
--- /dev/null
+++ b/errhandlers/manga_validators.go
@@ -0,0 +1,70 @@
+/* MAL2Go - MyAnimeList V2 API wrapper for Go
+ * Copyright (C) 2022  Vidhu Kant Sharma <vidhukant@protonmail.ch>
+
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>. */
+
+package errhandlers
+
+// Checks if given field is valid
+func IsValidMangaField(field string) bool {
+  switch field {
+    case
+      "id",
+      "title",
+      "main_picture",
+      "alternative_titles",
+      "start_date",
+      "end_date",
+      "synopsis",
+      "mean",
+      "rank",
+      "popularity",
+      "num_list_users",
+      "num_scoring_users",
+      "nsfw",
+      "created_at",
+      "updated_at",
+      "media_type",
+      "status",
+      "genres",
+      "my_list_status",
+      "num_volumes",
+      "num_chapters",
+      "authors",
+      "pictures",
+      "background",
+      "related_anime",
+      "related_manga",
+      "recommendations",
+      "serialization": return true
+    }
+  return false
+}
+
+// Checks if given ranking type is valid
+func IsValidMangaRankingType(rankingType string) bool {
+  switch rankingType {
+    case
+      "all",
+      "manga",
+      "novels",
+      "oneshots",
+      "doujin",
+      "manhwa",
+      "manhua",
+      "bypopularity",
+      "favorite": return true
+    }
+  return false
+}