From eb292a8d7097ea5ee2ff726261be83083a2a054f Mon Sep 17 00:00:00 2001
From: chenjigeng <178854407@qq.com>
Date: Sat, 19 Dec 2020 19:42:52 +0800
Subject: [PATCH 1/2] fix: host.isKnownTypesPackageName maybe undefined

---
 src/services/codefixes/fixCannotFindModule.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/services/codefixes/fixCannotFindModule.ts b/src/services/codefixes/fixCannotFindModule.ts
index a5d44c887b9a2..a2d3a73ad14ac 100644
--- a/src/services/codefixes/fixCannotFindModule.ts
+++ b/src/services/codefixes/fixCannotFindModule.ts
@@ -52,6 +52,6 @@ namespace ts.codefix {
     function getTypesPackageNameToInstall(packageName: string, host: LanguageServiceHost, diagCode: number): string | undefined {
         return diagCode === errorCodeCannotFindModule
             ? (JsTyping.nodeCoreModules.has(packageName) ? "@types/node" : undefined)
-            : (host.isKnownTypesPackageName!(packageName) ? getTypesPackageName(packageName) : undefined); // TODO: GH#18217
+            : (host.isKnownTypesPackageName?.(packageName) ? getTypesPackageName(packageName) : undefined); // TODO: GH#18217
     }
 }

From c02335e036ab26b7e820d2bc0339960ab0518c06 Mon Sep 17 00:00:00 2001
From: chenjigeng <178854407@qq.com>
Date: Sun, 20 Dec 2020 15:44:26 +0800
Subject: [PATCH 2/2] feat: remove GH#18217 comment

---
 src/services/codefixes/fixCannotFindModule.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/services/codefixes/fixCannotFindModule.ts b/src/services/codefixes/fixCannotFindModule.ts
index a2d3a73ad14ac..482480d84205d 100644
--- a/src/services/codefixes/fixCannotFindModule.ts
+++ b/src/services/codefixes/fixCannotFindModule.ts
@@ -52,6 +52,6 @@ namespace ts.codefix {
     function getTypesPackageNameToInstall(packageName: string, host: LanguageServiceHost, diagCode: number): string | undefined {
         return diagCode === errorCodeCannotFindModule
             ? (JsTyping.nodeCoreModules.has(packageName) ? "@types/node" : undefined)
-            : (host.isKnownTypesPackageName?.(packageName) ? getTypesPackageName(packageName) : undefined); // TODO: GH#18217
+            : (host.isKnownTypesPackageName?.(packageName) ? getTypesPackageName(packageName) : undefined);
     }
 }