Add repo vscode extensions recommendation (#99)

[poolifier.git] / src / fixed.ts

diff --git a/src/fixed.ts b/src/fixed.ts
index dee28c53fc00d0f62f5d9ea753a8ecad3151bba3..d2c6ba0c2fd542c8dd928d08ad6f54902224734b 100644 (file)
--- a/src/fixed.ts
+++ b/src/fixed.ts
@@ -1,7 +1,4 @@
-import { MessageChannel, SHARE_ENV, Worker, isMainThread } from 'worker_threads'
-
-function empty () {}
-const _void = {}
+import { isMainThread, MessageChannel, SHARE_ENV, Worker } from 'worker_threads'
 
 export type Draft<T> = { -readonly [P in keyof T]?: T[P] }
 
@@ -36,7 +33,8 @@ export interface FixedThreadPoolOptions {
  * @author [Alessandro Pio Ardizio](https://github.com/pioardi)
  * @since 0.0.1
  */
-export default class FixedThreadPool<Data = any, Response = any> {
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export class FixedThreadPool<Data = any, Response = any> {
   public readonly workers: WorkerWithMessageChannel[] = []
   public nextWorker: number = 0
 
@@ -46,7 +44,7 @@ export default class FixedThreadPool<Data = any, Response = any> {
     number
   >()
 
-  protected _id: number = 0
+  protected id: number = 0
 
   /**
    * @param numThreads Num of threads for this worker pool.
@@ -61,12 +59,13 @@ export default class FixedThreadPool<Data = any, Response = any> {
     if (!isMainThread) {
       throw new Error('Cannot start a thread pool from a worker thread !!!')
     }
+    // TODO christopher 2021-02-07: Improve this check e.g. with a pattern or blank check
     if (!this.filePath) {
       throw new Error('Please specify a file with a worker implementation')
     }
 
     for (let i = 1; i <= this.numThreads; i++) {
-      this._newWorker()
+      this.newWorker()
     }
   }
 
@@ -82,34 +81,48 @@ export default class FixedThreadPool<Data = any, Response = any> {
    * @param data The input for the task specified.
    * @returns Promise that is resolved when the task is done.
    */
-  public async execute (data: Data): Promise<Response> {
+  public execute (data: Data): Promise<Response> {
     // configure worker to handle message with the specified task
-    const worker = this._chooseWorker()
-    this.tasks.set(worker, this.tasks.get(worker) + 1)
-    const id = ++this._id
-    const res = this._execute(worker, id)
-    worker.postMessage({ data: data || _void, _id: id })
+    const worker = this.chooseWorker()
+    const previousWorkerIndex = this.tasks.get(worker)
+    if (previousWorkerIndex !== undefined) {
+      this.tasks.set(worker, previousWorkerIndex + 1)
+    } else {
+      throw Error('Worker could not be found in tasks map')
+    }
+    const id = ++this.id
+    const res = this.internalExecute(worker, id)
+    worker.postMessage({ data: data || {}, id: id })
     return res
   }
 
-  protected _execute (
+  protected internalExecute (
     worker: WorkerWithMessageChannel,
     id: number
   ): Promise<Response> {
     return new Promise((resolve, reject) => {
-      const listener = (message) => {
-        if (message._id === id) {
-          worker.port2.removeListener('message', listener)
-          this.tasks.set(worker, this.tasks.get(worker) - 1)
+      const listener = (message: {
+        id: number
+        error?: string
+        data: Response
+      }): void => {
+        if (message.id === id) {
+          worker.port2?.removeListener('message', listener)
+          const previousWorkerIndex = this.tasks.get(worker)
+          if (previousWorkerIndex !== undefined) {
+            this.tasks.set(worker, previousWorkerIndex + 1)
+          } else {
+            throw Error('Worker could not be found in tasks map')
+          }
           if (message.error) reject(message.error)
           else resolve(message.data)
         }
       }
-      worker.port2.on('message', listener)
+      worker.port2?.on('message', listener)
     })
   }
 
-  protected _chooseWorker (): WorkerWithMessageChannel {
+  protected chooseWorker (): WorkerWithMessageChannel {
     if (this.workers.length - 1 === this.nextWorker) {
       this.nextWorker = 0
       return this.workers[this.nextWorker]
@@ -119,14 +132,14 @@ export default class FixedThreadPool<Data = any, Response = any> {
     }
   }
 
-  protected _newWorker (): WorkerWithMessageChannel {
+  protected newWorker (): WorkerWithMessageChannel {
     const worker: WorkerWithMessageChannel = new Worker(this.filePath, {
       env: SHARE_ENV
     })
-    worker.on('error', this.opts.errorHandler || empty)
-    worker.on('online', this.opts.onlineHandler || empty)
+    worker.on('error', this.opts.errorHandler ?? (() => {}))
+    worker.on('online', this.opts.onlineHandler ?? (() => {}))
     // TODO handle properly when a thread exit
-    worker.on('exit', this.opts.exitHandler || empty)
+    worker.on('exit', this.opts.exitHandler ?? (() => {}))
     this.workers.push(worker)
     const { port1, port2 } = new MessageChannel()
     worker.postMessage({ parent: port1 }, [port1])
@@ -134,11 +147,9 @@ export default class FixedThreadPool<Data = any, Response = any> {
     worker.port2 = port2
     // we will attach a listener for every task,
     // when task is completed the listener will be removed but to avoid warnings we are increasing the max listeners size
-    worker.port2.setMaxListeners(this.opts.maxTasks || 1000)
+    worker.port2.setMaxListeners(this.opts.maxTasks ?? 1000)
     // init tasks map
     this.tasks.set(worker, 0)
     return worker
   }
 }
-
-module.exports = FixedThreadPool