Fix declaration file check

Resolves #2647

Author: Gerrit0

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Unreleased
 
+### Bug Fixes
+
+-   The `suppressCommentWarningsInDeclarationFiles` option now correctly ignores warnings in `.d.cts` and `.d.mts` files, #2647.
+
 ## v0.26.5 (2024-07-21)
 
 ### Features

src/lib/converter/comments/parser.ts

@@ -18,6 +18,7 @@ import type {
 } from "../../internationalization/internationalization";
 import { FileRegistry } from "../../models/FileRegistry";
 import { textContent, TextParserReentryState } from "./textParser";
+import { hasDeclarationFileExtension } from "../../utils/fs";
 
 interface LookaheadGenerator<T> {
     done(): boolean;
@@ -111,7 +112,7 @@ export function parseComment(
     function warningImpl(message: TranslatedString, token: Token) {
         if (
             config.suppressCommentWarningsInDeclarationFiles &&
-            file.fileName.endsWith(".d.ts")
+            hasDeclarationFileExtension(file.fileName)
         ) {
             return;
         }

src/lib/utils/fs.ts

@@ -271,6 +271,10 @@ export function hasTsExtension(path: string): boolean {
     return /\.[cm]?ts$|\.tsx$/.test(path);
 }
 
+export function hasDeclarationFileExtension(path: string) {
+    return /\.d\.[cm]?ts$/.test(path);
+}
+
 export function discoverInParentDir<T extends {}>(
     name: string,
     dir: string,