Correção de bug na formatação de CPF + Criação de novo parâmetro

lib/src/formatters/cpf_input_formatter.dart

@@ -2,41 +2,54 @@ import 'package:brasil_fields/src/interfaces/compoundable_formatter.dart';
 import 'package:flutter/services.dart';
 
 /// Formata o valor do campo com a mascara de CPF: `XXX.XXX.XXX-XX`
-class CpfInputFormatter extends TextInputFormatter
-    implements CompoundableFormatter {
+class CpfInputFormatter extends TextInputFormatter implements CompoundableFormatter {
+  final bool deleteSeparatorsAutomatically;
+  CpfInputFormatter({this.deleteSeparatorsAutomatically = true});
+
   // Define o tamanho máximo do campo.
   @override
-  int get maxLength => 11;
+  int get maxLength => 14;
 
   @override
   TextEditingValue formatEditUpdate(
-      TextEditingValue oldValue, TextEditingValue newValue) {
+    TextEditingValue oldValue, TextEditingValue newValue) {
     // verifica o tamanho máximo do campo
     if (newValue.text.length > maxLength) return oldValue;
 
-    var posicaoCursor = newValue.selection.end;
+    // valida o parâmetro que indica se deve remover os separadores automaticamente ao apagar um número
+    if (newValue.text.length < oldValue.text.length) {
+      if (deleteSeparatorsAutomatically == true) {
+        if (newValue.text.endsWith('.') || newValue.text.endsWith('-')) {
+          return newValue.copyWith(
+            text: newValue.text.substring(0, newValue.text.length - 1),
+            selection: TextSelection.collapsed(offset: newValue.selection.end - 1),
+          );
+        }
+        return newValue;
+      } else {
+        return newValue;
+      }
+    }
+
     var substrIndex = 0;
     final valorFinal = StringBuffer();
 
     if (newValue.text.length >= 4) {
       valorFinal.write('${newValue.text.substring(0, substrIndex = 3)}.');
-      if (newValue.selection.end >= 3) posicaoCursor++;
     }
     if (newValue.text.length >= 7) {
-      valorFinal.write('${newValue.text.substring(3, substrIndex = 6)}.');
-      if (newValue.selection.end >= 6) posicaoCursor++;
+      valorFinal.write('${newValue.text.substring(4, substrIndex = 7)}.');
     }
-    if (newValue.text.length >= 10) {
-      valorFinal.write('${newValue.text.substring(6, substrIndex = 9)}-');
-      if (newValue.selection.end >= 9) posicaoCursor++;
+    if (newValue.text.length >= 11) {
+      valorFinal.write('${newValue.text.substring(8, substrIndex = 11)}-');
     }
     if (newValue.text.length >= substrIndex) {
-      valorFinal.write(newValue.text.substring(substrIndex));
+      valorFinal.write(newValue.text.substring(substrIndex).replaceAll('.', '').replaceAll('-', ''));
     }
 
     return TextEditingValue(
       text: valorFinal.toString(),
-      selection: TextSelection.collapsed(offset: posicaoCursor),
+      selection: TextSelection.collapsed(offset: valorFinal.length),
     );
   }
 }

test/cpf_test.dart

@@ -1,4 +1,6 @@
+import 'package:brasil_fields/src/formatters/cpf_input_formatter.dart';
 import 'package:brasil_fields/src/validators/validators.dart';
+import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
@@ -54,4 +56,17 @@ void main() {
   test('Test CPF strip', () {
     expect(CPFValidator.strip('334.616.710-02'), '33461671002');
   });
+
+  test('Test CpfInputFormatter', () {
+    expect(
+      CpfInputFormatter().formatEditUpdate(
+        const TextEditingValue(text: '334.616.71'), // oldValue
+        const TextEditingValue(text: '334.616.710'), // newValue
+      ),
+      const TextEditingValue(
+        text: '334.616.710-', // newValue formatted
+        selection: TextSelection.collapsed(offset: 12),
+      ),
+    );
+  });
 }