Bugfix in sorterByMetadataField - reverse order working correctly now

- new unit tests

src/custom-sort/custom-sort.spec.ts

@@ -2274,3 +2274,38 @@ describe('CustomSortOrder.byMetadataFieldAlphabeticalReverse', () => {
 		expect(result3).toBe(SORT_ITEMS_ARE_EQUAL)
 	})
 })
+
+describe('sorterByMetadataField', () => {
+	it.each([
+		[true,'abc','def',-1, 'a', 'a'],
+		[true,'xyz','klm',1, 'b', 'b'],
+		[true,'mmm','mmm',0, 'c', 'c'],
+		[true,'mmm','mmm',-1, 'd', 'e'],
+		[true,'mmm','mmm',1, 'e', 'd'],
+		[true,'abc',undefined,-1, 'a','a'],
+		[true,undefined,'klm',1, 'b','b'],
+		[true,undefined,undefined,0, 'a','a'],
+		[true,undefined,undefined,-1, 'a','b'],
+		[true,undefined,undefined,1, 'd','c'],
+		[false,'abc','def',1, 'a', 'a'],
+		[false,'xyz','klm',-1, 'b', 'b'],
+		[false,'mmm','mmm',0, 'c', 'c'],
+		[false,'mmm','mmm',1, 'd', 'e'],
+		[false,'mmm','mmm',-1, 'e', 'd'],
+		[false,'abc',undefined,1, 'a','a'],
+		[false,undefined,'klm',-1, 'b','b'],
+		[false,undefined,undefined,0, 'a','a'],
+		[false,undefined,undefined,1, 'a','b'],
+		[false,undefined,undefined,-1, 'd','c'],
+
+	])('straight order %s, comparing %s and %s should return %s for sortStrings %s and %s',
+		(straight: boolean, metadataA: string|undefined, metadataB: string|undefined, order: number, sortStringA: string, sortStringB) => {
+		const sorterFn = sorterByMetadataField(!straight, false)
+		const itemA: Partial<FolderItemForSorting> = {metadataFieldValue: metadataA, sortString: sortStringA}
+		const itemB: Partial<FolderItemForSorting> = {metadataFieldValue: metadataB, sortString: sortStringB}
+		const result = sorterFn(itemA as FolderItemForSorting, itemB as FolderItemForSorting)
+
+		// then
+		expect(result).toBe(order)
+	})
+})

src/custom-sort/custom-sort.ts

@@ -71,7 +71,7 @@ const TrueAlphabetical: boolean = true
 const ReverseOrder: boolean = true
 const StraightOrder: boolean = false
 
-const sorterByMetadataField:(reverseOrder?: boolean, trueAlphabetical?: boolean) => SorterFn = (reverseOrder: boolean, trueAlphabetical?: boolean) => {
+export const sorterByMetadataField:(reverseOrder?: boolean, trueAlphabetical?: boolean) => SorterFn = (reverseOrder: boolean, trueAlphabetical?: boolean) => {
 	const collatorCompareFn: CollatorCompareFn = trueAlphabetical ? CollatorTrueAlphabeticalCompare : CollatorCompare
 	return (a: FolderItemForSorting, b: FolderItemForSorting) => {
 		if (reverseOrder) {
@@ -87,8 +87,8 @@ const sorterByMetadataField:(reverseOrder?: boolean, trueAlphabetical?: boolean)
 			}
 		}
 		// Item with metadata goes before the w/o metadata
-		if (a.metadataFieldValue) return reverseOrder ? 1 : -1
+		if (a.metadataFieldValue) return -1
-		if (b.metadataFieldValue) return reverseOrder ? -1 : 1
+		if (b.metadataFieldValue) return 1
 		// Fallback -> requested sort by metadata, yet none of two items contain it, use alphabetical by name
 		return collatorCompareFn(a.sortString, b.sortString)
 	}