convertFunctionToEs6Class: Copy comments from constructor to class (#22738)

src/services/codefixes/convertFunctionToEs6Class.ts

@@ -49,6 +49,8 @@ namespace ts.codefix {
             return undefined;
         }
 
+        copyComments(ctorDeclaration, newClassDeclaration, sourceFile);
+
         // Because the preceding node could be touched, we need to insert nodes before delete nodes.
         changes.insertNodeAfter(sourceFile, precedingNode, newClassDeclaration);
         for (const deleteCallback of deletes) {

src/services/textChanges.ts

@@ -221,6 +221,7 @@ namespace ts.textChanges {
             return this;
         }
 
+        /** Warning: This deletes comments too. See `copyComments` in `convertFunctionToEs6Class`. */
         public deleteNode(sourceFile: SourceFile, node: Node, options: ConfigurableStartEnd = {}) {
             const startPosition = getAdjustedStartPosition(sourceFile, node, options, Position.FullStart);
             const endPosition = getAdjustedEndPosition(sourceFile, node, options);

tests/cases/fourslash/server/convertFunctionToEs6Class-server.ts

@@ -14,9 +14,8 @@
 verify.codeFix({
     description: "Convert function to an ES2015 class",
     newFileContent:
-// NOTE: '// Comment' should be included, but due to incorrect handling of trivia,
-// it's omitted right now.
-`class fn {\r
+`// Comment\r
+class fn {\r
     constructor() {\r
         this.baz = 10;\r
     }\r