refactor: avoid parts

lib/src/codegen/js_interop.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/constant.dart';
 import 'package:analyzer/src/generated/element.dart';
-import 'package:analyzer/src/generated/constant.dart';
+import 'package:analyzer/src/generated/resolver.dart' show TypeProvider;
+
+import '../utils.dart';
 
 bool _isJsLibType(String expectedName, Element e) =>
     e?.name == expectedName && _isJsLib(e.library);
 
 /// Returns true if [e] represents any library from `package:js` or is the
 /// internal `dart:_js_helper` library.
 bool _isJsLib(LibraryElement e) {
   if (e == null) return false;
   var uri = e.source.uri;
   if (uri.scheme == 'package' && uri.path.startsWith('js/')) return true;
@@ skipping 32 matching lines @@
     _isBuiltinAnnotation(value, '_foreign_helper', 'JSExportName');
 
 bool isJsName(DartObjectImpl value) =>
     _isBuiltinAnnotation(value, '_js_helper', 'JSName');
 
 bool isJsPeerInterface(DartObjectImpl value) =>
     _isBuiltinAnnotation(value, '_js_helper', 'JsPeerInterface');
 
 bool isNativeAnnotation(DartObjectImpl value) =>
     _isBuiltinAnnotation(value, '_js_helper', 'Native');
+
+/// Returns the name value of the `JSExportName` annotation (when compiling
+/// the SDK), or `null` if there's none. This is used to control the name
+/// under which functions are compiled and exported.
+String getJSExportName(Element e, TypeProvider types) {
+  if (!e.source.isInSystemLibrary) {
+    return null;
+  }
+  var jsName = findAnnotation(e, isJSExportNameAnnotation);
+  return getConstantField(jsName, 'name', types.stringType)?.toStringValue();
+}