✅ ✨ Adds truncateMiddle extension

lib/string_extensions.dart

@@ -1577,4 +1577,34 @@ extension MiscExtensions on String? {
     }
     return '${this!.substring(0, length)}...';
   }
+
+  /// Truncates a long `String` in the middle while retaining the beginning and the end.
+  ///
+  /// [maxChars] must be more than 0.
+  ///
+  /// If [maxChars] > String.length the same `String` is returned without truncation.
+  ///
+  /// ### Example
+  ///
+  /// ```dart
+  /// String f = 'congratulations';
+  /// String truncated = f.truncateMiddle(5); // Returns 'con...ns'
+  String? truncateMiddle(int maxChars) {
+    if (this == null) {
+      return null;
+    }
+    if (this!.isEmpty) {
+      return this;
+    }
+    if (maxChars <= 0) {
+      return this;
+    }
+    if (maxChars > this!.length) {
+      return this;
+    }
+
+    int leftChars = (maxChars / 2).ceil();
+    int rightChars = maxChars - leftChars;
+    return '${this!.first(n: leftChars)}...${this!.last(n: rightChars)}';
+  }
 }

test/string_extensions_test.dart

@@ -675,4 +675,17 @@ void main() {
       expect(t1.truncate(-13), 'peanutbutter');
     },
   );
+  test(
+    'Truncates the string in the middle with "..." keeping start and ending the same',
+    () {
+      String t1 = 'peanutbutter';
+      expect(t1.truncateMiddle(3), 'pe...r');
+      expect(t1.truncateMiddle(0), 'peanutbutter');
+      expect(t1.truncateMiddle(4), 'pe...er');
+      expect(t1.truncateMiddle(2), 'p...r');
+      expect(t1.truncateMiddle(1), 'p...');
+      expect(t1.truncateMiddle(13), 'peanutbutter');
+      expect(t1.truncateMiddle(-13), 'peanutbutter');
+    },
+  );
 }