fix: gives minimum priority to the "void" character

- This means that "a" will now come before "aa".
- This reflects the behavior of `localeCompare`.

test/compare.test.ts

@@ -249,6 +249,21 @@ describe('compare', () => {
         }),
       ).toBe(0)
     })
+
+    it('gives minimum priority to void', () => {
+      expect(
+        compare(createTestNode({ name: 'a' }), createTestNode({ name: '' }), {
+          ...compareOptions,
+          alphabet: 'a',
+        }),
+      ).toBe(-1)
+      expect(
+        compare(createTestNode({ name: '' }), createTestNode({ name: 'a' }), {
+          ...compareOptions,
+          alphabet: 'a',
+        }),
+      ).toBe(1)
+    })
   })
 
   let createTestNode = ({ name }: { name: string }): SortingNode =>

utils/compare.ts

@@ -122,9 +122,10 @@ let getCustomSortingFunction = <T extends SortingNode>(
   return (aNode: T, bNode: T) => {
     let aValue = formatString(nodeValueGetter(aNode))
     let bValue = formatString(nodeValueGetter(bNode))
+    let minLength = Math.min(aValue.length, bValue.length)
     // Iterate character by character
     // eslint-disable-next-line unicorn/no-for-loop
-    for (let i = 0; i < aValue.length; i++) {
+    for (let i = 0; i < minLength; i++) {
       let aCharacter = aValue[i]
       let bCharacter = bValue[i]
       let indexOfA = indexByCharacters.get(aCharacter)
@@ -135,6 +136,12 @@ let getCustomSortingFunction = <T extends SortingNode>(
         return convertBooleanToSign(indexOfA - indexOfB > 0)
       }
     }
+    if (aValue.length > bValue.length) {
+      return -1
+    }
+    if (bValue.length > aValue.length) {
+      return 1
+    }
     return 0
   }
 }