Use new casing-utils from source_helper

Drop internal implementations and tests

Author: kevmoo

json_serializable/lib/src/helper_core.dart

@@ -14,7 +14,6 @@ import 'type_helper.dart';
 import 'type_helper_ctx.dart';
 import 'type_helpers/config_types.dart';
 import 'unsupported_type_error.dart';
-import 'utils.dart';
 
 abstract class HelperCore {
   final ClassElement element;
@@ -38,7 +37,7 @@ abstract class HelperCore {
       escapeDartString(nameAccess(field));
 
   @protected
-  String get prefix => '_\$${nonPrivateName(element.name)}';
+  String get prefix => '_\$${element.name.nonPrivate}';
 
   /// Returns a [String] representing the type arguments that exist on
   /// [element].

json_serializable/lib/src/json_key_utils.dart

@@ -245,11 +245,11 @@ String _encodedFieldName(
     case FieldRename.none:
       return fieldElement.name;
     case FieldRename.snake:
-      return snakeCase(fieldElement.name);
+      return fieldElement.name.snake;
     case FieldRename.kebab:
-      return kebabCase(fieldElement.name);
+      return fieldElement.name.kebab;
     case FieldRename.pascal:
-      return pascalCase(fieldElement.name);
+      return fieldElement.name.pascal;
     default:
       throw ArgumentError.value(
         classAnnotation,

json_serializable/lib/src/utils.dart

@@ -26,33 +26,6 @@ ConstantReader jsonKeyAnnotation(FieldElement element) =>
 bool hasJsonKeyAnnotation(FieldElement element) =>
     _jsonKeyAnnotation(element) != null;
 
-final _upperCase = RegExp('[A-Z]');
-
-String kebabCase(String input) => _fixCase(input, '-');
-
-String snakeCase(String input) => _fixCase(input, '_');
-
-String pascalCase(String input) {
-  if (input.isEmpty) {
-    return '';
-  }
-
-  return input[0].toUpperCase() + input.substring(1);
-}
-
-String _fixCase(String input, String separator) =>
-    input.replaceAllMapped(_upperCase, (match) {
-      var lower = match.group(0)!.toLowerCase();
-
-      if (match.start > 0) {
-        lower = '$separator$lower';
-      }
-
-      return lower;
-    });
-
-String nonPrivateName(String input) => input.replaceFirst(RegExp(r'^_*'), '');
-
 Never throwUnsupported(FieldElement element, String message) =>
     throw InvalidGenerationSourceError(
         'Error with `@JsonKey` on `${element.name}`. $message',

json_serializable/pubspec.yaml

@@ -19,7 +19,7 @@ dependencies:
   meta: ^1.3.0
   path: ^1.8.0
   source_gen: ^1.0.0
-  source_helper: ^1.2.1
+  source_helper: ^1.3.0
 
 dev_dependencies:
   build_runner: ^2.0.0

json_serializable/test/utils_test.dart

@@ -5,9 +5,9 @@ import 'dart:async';
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:build/build.dart';
-import 'package:json_serializable/src/utils.dart';
 import 'package:pub_semver/pub_semver.dart';
 import 'package:source_gen/source_gen.dart';
+import 'package:source_helper/source_helper.dart';
 import 'package:yaml/yaml.dart';
 
 Builder docBuilder([_]) => _DocBuilder();
@@ -144,7 +144,7 @@ class _FieldInfo implements Comparable<_FieldInfo> {
       return '';
     }
 
-    return snakeCase(_classField!.name);
+    return _classField!.name.snake;
   }
 
   _FieldInfo(this._keyField, this._classField);