Merge pull request #296 from Workiva/handle-useRef-null

FED-3209 Remove explicit null passed to useRef
Workiva · Oct 1, 2024 · 8fef280 · 8fef280
2 parents 3c1a681 + e7f232a
commit 8fef280
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Showing 2 changed files with 33 additions and 4 deletions.
diff --git a/lib/src/dart3_suggestors/null_safety_prep/use_ref_init_migration.dart b/lib/src/dart3_suggestors/null_safety_prep/use_ref_init_migration.dart
@@ -15,6 +15,7 @@
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:codemod/codemod.dart';
+import 'package:collection/collection.dart';
 
 /// Suggestor that finds instances of `useRef` function invocations that
 /// pass an argument, and replaces them with `useRefInit` to prep for
@@ -24,9 +25,11 @@ import 'package:codemod/codemod.dart';
 ///
 /// ```dart
 /// // Before
-/// final ref = useRef(someNonNulLValue);
+/// final ref1 = useRef(someNonNulLValue);
+/// final ref2 = useRef<Element>(null);
 /// // After
-/// final ref = useRefInit(someNonNulLValue);
+/// final ref1 = useRefInit(someNonNulLValue);
+/// final ref2 = useRef<Element>();
 /// ```
 class UseRefInitMigration extends RecursiveAstVisitor
     with AstVisitingSuggestor {
@@ -44,8 +47,14 @@ class UseRefInitMigration extends RecursiveAstVisitor
       }
 
       if (fnName == 'useRef') {
-        yieldPatch('useRefInit', possibleInvocation.function.offset,
-            possibleInvocation.function.end);
+        final argument = node.arguments.singleOrNull;
+        if (argument is NullLiteral) {
+          // Remove unnecessary null argument
+          yieldPatch('', argument.offset, argument.end);
+        } else {
+          yieldPatch('useRefInit', possibleInvocation.function.offset,
+              possibleInvocation.function.end);
+        }
       }
     }
   }

diff --git a/test/dart3_suggestors/null_safety_prep/use_ref_init_migration_test.dart b/test/dart3_suggestors/null_safety_prep/use_ref_init_migration_test.dart
@@ -104,5 +104,25 @@ void main() {
             '''),
       );
     });
+
+    test('removes unnecessary null arguments', () async {
+      await testSuggestor(
+        expectedPatchCount: 2,
+        input: withOverReactImport('''
+              useTestHook() {
+                final foo = useRef(null);
+                final bar = useRef<String>(null);
+                return [foo, bar];
+              }
+            '''),
+        expectedOutput: withOverReactImport('''
+              useTestHook() {
+                final foo = useRef();
+                final bar = useRef<String>();
+                return [foo, bar];
+              }
+            '''),
+      );
+    });
   });
 }