Upgrade TS to 3.7.3

CHANGELOG.md

@@ -6,7 +6,7 @@ The version headers in this history reflect the versions of Apollo Server itself
 
 > The changes noted within this `vNEXT` section have not been released yet.  New PRs and commits which introduce changes should include an entry in this `vNEXT` section as part of their development.  When a release is being prepared, a new header will be (manually) created below and the the appropriate changes within that release will be moved into the new section.
 
-- _Nothing yet.  Stay tuned!_
+- `apollo-server-core`: Upgrade TS to 3.7.3 [#3618](https://github.com/apollographql/apollo-server/pull/3618)
 
 ### v2.9.14
 

package.json

@@ -121,7 +121,7 @@
     "supertest": "4.0.2",
     "test-listen": "1.1.0",
     "ts-jest": "24.2.0",
-    "typescript": "3.6.2",
+    "typescript": "3.7.3",
     "ws": "6.2.1"
   },
   "jest": {

packages/apollo-server-core/src/utils/dispatcher.ts

@@ -1,19 +1,16 @@
+import { GraphQLRequestListener } from "apollo-server-plugin-base";
+
 type AnyFunction = (...args: any[]) => any;
 type Args<F> = F extends (...args: infer A) => any ? A : never;
-type FunctionPropertyNames<T, F extends AnyFunction = AnyFunction> = {
-  [K in keyof T]: T[K] extends F ? K : never;
-}[keyof T];
 type AsFunction<F> = F extends AnyFunction ? F : never;
 type UnwrapPromise<T> = T extends Promise<infer U> ? U : T;
 
 type DidEndHook<TArgs extends any[]> = (...args: TArgs) => void;
 
-export class Dispatcher<T> {
+export class Dispatcher<T extends GraphQLRequestListener> {
   constructor(protected targets: T[]) {}
 
-  public async invokeHookAsync<
-    TMethodName extends FunctionPropertyNames<Required<T>>
-  >(
+  public async invokeHookAsync<TMethodName extends keyof T>(
     methodName: TMethodName,
     ...args: Args<T[TMethodName]>
   ): Promise<UnwrapPromise<ReturnType<AsFunction<T[TMethodName]>>>[]> {
@@ -27,9 +24,7 @@ export class Dispatcher<T> {
     );
   }
 
-  public async invokeHooksUntilNonNull<
-    TMethodName extends FunctionPropertyNames<Required<T>>
-  >(
+  public async invokeHooksUntilNonNull<TMethodName extends keyof T>(
     methodName: TMethodName,
     ...args: Args<T[TMethodName]>
   ): Promise<UnwrapPromise<ReturnType<AsFunction<T[TMethodName]>>> | null> {
@@ -47,10 +42,7 @@ export class Dispatcher<T> {
   }
 
   public invokeDidStartHook<
-    TMethodName extends FunctionPropertyNames<
-      Required<T>,
-      (...args: any[]) => AnyFunction | void
-    >,
+    TMethodName extends keyof T,
     TEndHookArgs extends Args<ReturnType<AsFunction<T[TMethodName]>>>
   >(
     methodName: TMethodName,