Improve error handling of API (#4345)

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* Update attached_notes.ts

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* Refactor

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* Update call.ts

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* ✌️

* Fix

src/server/api/endpoints/notes/favorites/delete.ts

@@ -3,6 +3,7 @@ import ID, { transform } from '../../../../../misc/cafy-id';
 import Favorite from '../../../../../models/favorite';
 import Note from '../../../../../models/note';
 import define from '../../../define';
+import { ApiError } from '../../../error';
 
 export const meta = {
 	stability: 'stable',
@@ -25,17 +26,31 @@ export const meta = {
 				'en-US': 'Target note ID.'
 			}
 		}
+	},
+
+	errors: {
+		noSuchNote: {
+			message: 'No such note.',
+			code: 'NO_SUCH_NOTE',
+			id: '80848a2c-398f-4343-baa9-df1d57696c56'
+		},
+
+		notFavorited: {
+			message: 'You have not marked that note a favorite.',
+			code: 'NOT_FAVORITED',
+			id: 'b625fc69-635e-45e9-86f4-dbefbef35af5'
+		},
 	}
 };
 
-export default define(meta, (ps, user) => new Promise(async (res, rej) => {
+export default define(meta, async (ps, user) => {
 	// Get favoritee
 	const note = await Note.findOne({
 		_id: ps.noteId
 	});
 
 	if (note === null) {
-		return rej('note not found');
+		throw new ApiError(meta.errors.noSuchNote);
 	}
 
 	// if already favorited
@@ -45,7 +60,7 @@ export default define(meta, (ps, user) => new Promise(async (res, rej) => {
 	});
 
 	if (exist === null) {
-		return rej('already not favorited');
+		throw new ApiError(meta.errors.notFavorited);
 	}
 
 	// Delete favorite
@@ -53,6 +68,5 @@ export default define(meta, (ps, user) => new Promise(async (res, rej) => {
 		_id: exist._id
 	});
 
-	// Send response
-	res();
-}));
+	return;
+});