From 50e66724ecb17b83dfb87b1128ca9674f9b14e03 Mon Sep 17 00:00:00 2001
From: =?utf8?q?J=C3=A9r=C3=B4me=20Benoit?= <jerome.benoit@sap.com>
Date: Mon, 10 Apr 2023 13:41:53 +0200
Subject: [PATCH 1/1] refactor: enforce more worker type safety
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Signed-off-by: Jérôme Benoit <jerome.benoit@sap.com>
---
 src/pools/pool.ts    |  3 ++-
 src/pools/worker.ts  | 17 +++++++++++++----
 src/utility-types.ts |  1 +
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/pools/pool.ts b/src/pools/pool.ts
index 3c660031..f24d79e4 100644
--- a/src/pools/pool.ts
+++ b/src/pools/pool.ts
@@ -2,6 +2,7 @@ import EventEmitter from 'node:events'
 import type {
   ErrorHandler,
   ExitHandler,
+  IWorker,
   MessageHandler,
   OnlineHandler
 } from './worker'
@@ -31,7 +32,7 @@ export type PoolEvent = keyof typeof PoolEvents
 /**
  * Options for a poolifier pool.
  */
-export interface PoolOptions<Worker> {
+export interface PoolOptions<Worker extends IWorker> {
   /**
    * A function that will listen for message event on each worker.
    */
diff --git a/src/pools/worker.ts b/src/pools/worker.ts
index 4ff2c494..1e23ee87 100644
--- a/src/pools/worker.ts
+++ b/src/pools/worker.ts
@@ -3,22 +3,31 @@ import type { CircularArray } from '../circular-array'
 /**
  * Callback invoked if the worker has received a message.
  */
-export type MessageHandler<Worker> = (this: Worker, m: unknown) => void
+export type MessageHandler<Worker extends IWorker> = (
+  this: Worker,
+  m: unknown
+) => void
 
 /**
  * Callback invoked if the worker raised an error.
  */
-export type ErrorHandler<Worker> = (this: Worker, e: Error) => void
+export type ErrorHandler<Worker extends IWorker> = (
+  this: Worker,
+  e: Error
+) => void
 
 /**
  * Callback invoked when the worker has started successfully.
  */
-export type OnlineHandler<Worker> = (this: Worker) => void
+export type OnlineHandler<Worker extends IWorker> = (this: Worker) => void
 
 /**
  * Callback invoked when the worker exits successfully.
  */
-export type ExitHandler<Worker> = (this: Worker, code: number) => void
+export type ExitHandler<Worker extends IWorker> = (
+  this: Worker,
+  code: number
+) => void
 
 /**
  * Worker task interface.
diff --git a/src/utility-types.ts b/src/utility-types.ts
index b5611f9e..544b4cd0 100644
--- a/src/utility-types.ts
+++ b/src/utility-types.ts
@@ -39,6 +39,7 @@ export interface MessageValue<
    * Reference to main worker.
    *
    * Only for internal use.
+   * @internal
    */
   readonly parent?: MainWorker
 }
-- 
2.34.1