Fix two issues with ConvertToTypeOnlyExport codefix (#40490)

* Modify test case to reproduce error

* Fix TypeOnlyExport codefix to work with 3 or more type exports in the same declaration

The check to ensure that a fixed export declaration wasn't fixed again
was reversed. This only surfaced when 3 or more type exports existed in
the same declaration.

* Add failing test cases for comments being duplicated

* Fix convertToTypeOnlyExport codefix from duplicating leading comments

* Simplify convertToTypeOnlyExport when change is just inserting `type` keyword

Co-authored-by: Andrew Branch <[email protected]>

Author: Blasz

src/services/codefixes/convertToTypeOnlyExport.ts

@@ -15,7 +15,7 @@ namespace ts.codefix {
             const fixedExportDeclarations = new Map<string, true>();
             return codeFixAll(context, errorCodes, (changes, diag) => {
                 const exportSpecifier = getExportSpecifierForDiagnosticSpan(diag, context.sourceFile);
-                if (exportSpecifier && !addToSeen(fixedExportDeclarations, getNodeId(exportSpecifier.parent.parent))) {
+                if (exportSpecifier && addToSeen(fixedExportDeclarations, getNodeId(exportSpecifier.parent.parent))) {
                     fixSingleExportDeclaration(changes, exportSpecifier, context);
                 }
             });
@@ -35,16 +35,7 @@ namespace ts.codefix {
         const exportDeclaration = exportClause.parent;
         const typeExportSpecifiers = getTypeExportSpecifiers(exportSpecifier, context);
         if (typeExportSpecifiers.length === exportClause.elements.length) {
-            changes.replaceNode(
-                context.sourceFile,
-                exportDeclaration,
-                factory.updateExportDeclaration(
-                    exportDeclaration,
-                    exportDeclaration.decorators,
-                    exportDeclaration.modifiers,
-                    /*isTypeOnly*/ true,
-                    exportClause,
-                    exportDeclaration.moduleSpecifier));
+            changes.insertModifierBefore(context.sourceFile, SyntaxKind.TypeKeyword, exportClause);
         }
         else {
             const valueExportDeclaration = factory.updateExportDeclaration(
@@ -61,7 +52,10 @@ namespace ts.codefix {
                 factory.createNamedExports(typeExportSpecifiers),
                 exportDeclaration.moduleSpecifier);
 
-            changes.replaceNode(context.sourceFile, exportDeclaration, valueExportDeclaration);
+            changes.replaceNode(context.sourceFile, exportDeclaration, valueExportDeclaration, {
+                leadingTriviaOption: textChanges.LeadingTriviaOption.IncludeAll,
+                trailingTriviaOption: textChanges.TrailingTriviaOption.Exclude
+            });
             changes.insertNodeAfter(context.sourceFile, exportDeclaration, typeExportDeclaration);
         }
     }

tests/cases/fourslash/codeFixConvertToTypeOnlyExport1.ts

@@ -7,12 +7,15 @@
 ////export type B = {};
 
 // @Filename: /b.ts
+/////* Comment */
 ////export { A, B } from './a';
 
 goTo.file("/b.ts");
 verify.codeFix({
   index: 0,
   description: ts.Diagnostics.Convert_to_type_only_export.message,
   errorCode: ts.Diagnostics.Re_exporting_a_type_when_the_isolatedModules_flag_is_provided_requires_using_export_type.code,
-  newFileContent: "export type { A, B } from './a';"
+  newFileContent:
+`/* Comment */
+export type { A, B } from './a';`
 });

tests/cases/fourslash/codeFixConvertToTypeOnlyExport3.ts

@@ -11,19 +11,34 @@
 ////export type T3 = {};
 ////export const V2 = {};
 ////export type T4 = {};
+////export type T5 = {};
 
 // @Filename: /c.ts
+////export type T6 = {};
+////export type T7 = {};
+
+// @Filename: /d.ts
+/////* Test comment */
 ////export { T1, V1, T2 } from './a';
-////export { T3, V2, T4 } from './b';
+////export { T3, V2, T4, T5 } from './b';
+////// TODO: fix messy formatting
+////export {
+////  T6 // need to export this
+////   , T7, /* and this */ } from    "./c";
+
 
-goTo.file("/c.ts");
+goTo.file("/d.ts");
 verify.codeFixAll({
   fixAllDescription: ts.Diagnostics.Convert_all_re_exported_types_to_type_only_exports.message,
   fixId: "convertToTypeOnlyExport",
   newFileContent:
-`export { V1 } from './a';
+`/* Test comment */
+export { V1 } from './a';
 export type { T1, T2 } from './a';
 export { V2 } from './b';
-export type { T3, T4 } from './b';
-`
+export type { T3, T4, T5 } from './b';
+// TODO: fix messy formatting
+export type {
+  T6 // need to export this
+   , T7, /* and this */ } from    "./c";`
 });