From 576b8a7a2ffd7d35c54cd1579d7d0a9c5501d561 Mon Sep 17 00:00:00 2001
From: Johnson Chu <johnsoncodehk@gmail.com>
Date: Sat, 1 Jun 2024 04:27:11 +0800
Subject: [PATCH] feat(language-core): add option to resolve hidden extensions

---
 packages/language-core/lib/types.ts          |  4 ++++
 packages/typescript/lib/resolveModuleName.ts | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/packages/language-core/lib/types.ts b/packages/language-core/lib/types.ts
index 6f9d85c5..9d1cfa4b 100644
--- a/packages/language-core/lib/types.ts
+++ b/packages/language-core/lib/types.ts
@@ -97,6 +97,10 @@ export interface LanguagePlugin<T, K extends VirtualCode = VirtualCode> {
 		 * LSP + TS Plugin
 		 */
 		extraFileExtensions: ts.FileExtensionInfo[];
+		/**
+		 * LSP + TS Plugin
+		 */
+		resolveHiddenExtensions?: boolean;
 		/**
 		 * LSP + TS Plugin
 		 */
diff --git a/packages/typescript/lib/resolveModuleName.ts b/packages/typescript/lib/resolveModuleName.ts
index dc51797d..a6c429ea 100644
--- a/packages/typescript/lib/resolveModuleName.ts
+++ b/packages/typescript/lib/resolveModuleName.ts
@@ -52,6 +52,24 @@ export function createResolveModuleName<T>(
 						}
 					}
 				}
+				if (typescript.resolveHiddenExtensions && fileName.endsWith(`.d.ts`)) {
+					for (const { extension } of typescript.extraFileExtensions) {
+						const sourceFileName = fileName.slice(0, -`.d.ts`.length) + `.${extension}`;
+						if (fileExists(sourceFileName)) {
+							const sourceScript = getSourceScript(sourceFileName);
+							if (sourceScript?.generated) {
+								const serviceScript = sourceScript.generated.languagePlugin.typescript?.getServiceScript(sourceScript.generated.root);
+								if (serviceScript) {
+									toSourceFileInfo.set(fileName, {
+										sourceFileName,
+										extension: serviceScript.extension,
+									});
+									return true;
+								}
+							}
+						}
+					}
+				}
 			}
 			return host.fileExists(fileName);
 		},