diff --git a/src/backend/UpdateManger.ts b/src/backend/UpdateManger.ts
index e523494..a0a5e52 100644
--- a/src/backend/UpdateManger.ts
+++ b/src/backend/UpdateManger.ts
@@ -97,7 +97,7 @@ export type FSStatus = SharedStatus & {
     empty: boolean
 }
 
-export abstract class FSExtension extends Extension<FSStatus>{
+export abstract class FSExtension<Status extends FSStatus> extends Extension<FSStatus>{
     constructor(
         name: string, 
         protected readonly prefix: string){
@@ -106,7 +106,7 @@ export abstract class FSExtension extends Extension<FSStatus>{
             mkdir(path.resolve(prefix, name))
     }
 
-    public async status(): Promise<FSStatus>{
+    public async status(): Promise<Status | FSStatus>{
         const installed = await this.isInstalled()
         const outdated = await this.isOutdated()
         const exists = await this.exists()
@@ -149,12 +149,10 @@ type NPMStatus = FSStatus & {
 
 export class NPMExtension extends FSExtension<NPMStatus>{
 
-
     constructor(
-        name,
-        public localPrefix,
-    ){
-        super(name)
+        name: string,
+        prefix: string){
+        super(name, prefix)
     }
 
     public async status(): Promise<NPMStatus> {