Add generics to server add-on connection

Reviewed By: mweststrate

Differential Revision: D34307356

fbshipit-source-id: 27e61355a85995368ebb197c42d58f4145473567

desktop/flipper-common/src/ServerAddOn.tsx

@@ -48,13 +48,25 @@ export type FlipperPluginReceiverRes =
   | undefined
   | void;
 
-export type FlipperPluginReceiver = (
-  data: any,
+export type FlipperPluginReceiver<T> = (
+  data: T,
 ) => FlipperPluginReceiverRes | Promise<FlipperPluginReceiverRes>;
 
-export interface ServerAddOnPluginConnection {
-  send(method: string, params: unknown): void;
-  receive(method: string, receiver: FlipperPluginReceiver): void;
+export type EventsContract = Record<string, any>;
+export type MethodsContract = Record<string, (params: any) => Promise<any>>;
+
+export interface ServerAddOnPluginConnection<
+  Events extends EventsContract,
+  Methods extends MethodsContract,
+> {
+  send<T extends keyof Events & string>(
+    method: T,
+    ...params: Events[T] extends never ? [] : [Events[T]]
+  ): void;
+  receive<T extends keyof Methods & string>(
+    method: T,
+    receiver: FlipperPluginReceiver<Parameters<Methods[T]>[0]>,
+  ): void;
 }
 
 export interface FlipperServerForServerAddOn extends FlipperServer {
@@ -65,7 +77,10 @@ export interface FlipperServerForServerAddOn extends FlipperServer {
 }
 
 export type ServerAddOnCleanup = () => Promise<void>;
-export type ServerAddOn = (
-  connection: ServerAddOnPluginConnection,
+export type ServerAddOn<
+  Events extends EventsContract,
+  Methods extends MethodsContract,
+> = (
+  connection: ServerAddOnPluginConnection<Events, Methods>,
   {flipperServer}: {flipperServer: FlipperServerForServerAddOn},
 ) => Promise<ServerAddOnCleanup>;

desktop/flipper-common/src/index.tsx

@@ -47,6 +47,7 @@ export {
   getErrorFromErrorLike,
   deserializeRemoteError,
 } from './utils/errors';
+export {createControlledPromise} from './utils/controlledPromise';
 export * from './GK';
 export * from './clientUtils';
 export * from './settings';

desktop/flipper-common/src/utils/controlledPromise.tsx

@@ -0,0 +1,47 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+type Res<T> = {
+  promise: Promise<T>;
+  resolve: (...res: T extends void ? [] : [T]) => void;
+  reject: (reason: unknown) => void;
+} & (
+  | {
+      state: 'pending';
+      promiseVal: undefined;
+    }
+  | {state: 'resolved'; promiseVal: T}
+  | {state: 'rejected'; promiseVal: unknown}
+);
+
+export const createControlledPromise = <T,>(): Res<T> => {
+  let resolve!: Res<T>['resolve'];
+  let reject!: Res<T>['reject'];
+  let state: 'pending' | 'resolved' | 'rejected' = 'pending';
+  let promiseVal: T | unknown | undefined;
+  const promise = new Promise<T>((resolveP, rejectP) => {
+    resolve = ((val) => {
+      state = 'resolved';
+      promiseVal = val;
+      resolveP(val as T | PromiseLike<T>);
+    }) as typeof resolve;
+    reject = (err) => {
+      state = 'rejected';
+      promiseVal = err;
+      rejectP(err);
+    };
+  });
+  return {
+    promise,
+    resolve,
+    reject,
+    state,
+    promiseVal,
+  } as Res<T>;
+};