feat(event-emitter)!: add typed EventEmitter, remove legacy events

index.ts

@@ -22,7 +22,7 @@ export { Ticker } from './src/ticker/ticker';
 export { Worker } from './src/worker/worker';
 export { WorkerRunner } from './src/worker/worker-runner/worker-runner';
 export { WorkerPool } from './src/worker/worker-runner/worker-pool';
-export { events } from './src/events/events';
 export { logger } from './src/logger/logger';
 export { async } from './src/async/async';
 export { redis } from './src/redis-client';
+export * from './src/event';

src/event/event-emitter.ts

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c)
+ * Weyoss <weyoss@protonmail.com>
+ * https://github.com/weyoss
+ *
+ * This source code is licensed under the MIT license found in the LICENSE file
+ * in the root directory of this source tree.
+ */
+
+import { EventEmitter as Base } from 'events';
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export type TEventEmitterEvent = Record<string | symbol, (...args: any) => any>; // type-coverage:ignore-line
+
+export declare interface EventEmitter<Events extends TEventEmitterEvent>
+  extends Base {
+  on<E extends keyof Events>(event: E, listener: Events[E]): this;
+  once<E extends keyof Events>(event: E, listener: Events[E]): this;
+  emit<E extends keyof Events>(
+    event: E,
+    ...args: Parameters<Events[E]>
+  ): boolean;
+  removeAllListeners<E extends keyof Events>(event?: E): this;
+}
+
+// eslint-disable-next-line @typescript-eslint/no-unsafe-declaration-merging
+export class EventEmitter<
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  Events extends TEventEmitterEvent,
+> extends Base {}

src/events/events.ts → src/event/index.ts

@@ -7,11 +7,4 @@
  * in the root directory of this source tree.
  */
 
-export const events = {
-  GOING_UP: 'going_up',
-  UP: 'up',
-  GOING_DOWN: 'going_down',
-  DOWN: 'down',
-  ERROR: 'error',
-  TICK: 'tick',
-};
+export * from './event-emitter';

src/ticker/ticker.ts

@@ -7,14 +7,13 @@
  * in the root directory of this source tree.
  */
 
-import { TFunction } from '../../types';
-import { EventEmitter } from 'events';
-import { events } from '../events/events';
+import { TFunction, TEvent } from '../../types';
 import { PowerSwitch } from '../power-switch/power-switch';
 import { TickerError } from './errors';
 import { PanicError } from '../errors';
+import { EventEmitter } from '../event';
 
-export class Ticker extends EventEmitter {
+export class Ticker extends EventEmitter<TEvent> {
   protected powerManager = new PowerSwitch();
   protected onTickFn: TFunction;
   protected onNextTickFn: TFunction | null = null;
@@ -37,7 +36,7 @@ export class Ticker extends EventEmitter {
       clearTimeout(this.shutdownTimeout);
     }
     this.powerManager.commit();
-    this.emit(events.DOWN);
+    this.emit('down');
   }
 
   protected onTick(): void {
@@ -48,7 +47,7 @@ export class Ticker extends EventEmitter {
       this.onNextTickFn = null;
       tickFn();
     } else {
-      this.emit(events.ERROR, new PanicError(`Unexpected call`));
+      this.emit('error', new PanicError(`Unexpected call`));
     }
   }
 
@@ -63,9 +62,9 @@ export class Ticker extends EventEmitter {
   quit(): void {
     if (this.powerManager.isGoingUp()) {
       this.powerManager.rollback();
-      this.emit(events.DOWN);
+      this.emit('down');
     } else if (this.aborted && this.powerManager.isDown()) {
-      this.emit(events.DOWN);
+      this.emit('down');
     } else {
       this.powerManager.goingDown();
       if (this.timeout) {

src/worker/worker-runner/worker-runner.ts

@@ -7,19 +7,18 @@
  * in the root directory of this source tree.
  */
 
-import { ICallback, ILogger } from '../../../types';
+import { ICallback, ILogger, TEvent } from '../../../types';
 import { PowerSwitch } from '../../power-switch/power-switch';
-import { EventEmitter } from 'events';
 import { Ticker } from '../../ticker/ticker';
 import { ELockStatus, Lock } from '../../lock/lock';
 import { RedisClient } from '../../redis-client/redis-client';
-import { events } from '../../events/events';
 import { WorkerPool } from './worker-pool';
 import { Worker } from '../worker';
 import { async } from '../../async/async';
 import { LockAcquireError } from '../../lock/errors';
+import { EventEmitter } from '../../event';
 
-export class WorkerRunner extends EventEmitter {
+export class WorkerRunner extends EventEmitter<TEvent> {
   private readonly powerManager: PowerSwitch;
   private readonly ticker: Ticker;
   private readonly lock: Lock;
@@ -61,7 +60,7 @@ export class WorkerRunner extends EventEmitter {
       ],
       (err) => {
         if (!err || err instanceof LockAcquireError) this.ticker.nextTick();
-        else this.emit(events.ERROR, err);
+        else this.emit('error', err);
       },
     );
   };
@@ -71,7 +70,7 @@ export class WorkerRunner extends EventEmitter {
   };
 
   private stopTicker = (cb: ICallback<void>) => {
-    this.ticker.once(events.DOWN, cb);
+    this.ticker.once('down', cb);
     this.ticker.quit();
   };
 
@@ -84,15 +83,15 @@ export class WorkerRunner extends EventEmitter {
   }
 
   run = (): void => {
-    this.emit(events.UP);
+    this.emit('up');
     this.ticker.nextTick();
   };
 
   quit = (cb: ICallback<void>): void => {
     async.waterfall(
       [this.stopTicker, this.clearWorkerPool, this.releaseLock],
       () => {
-        this.emit(events.DOWN);
+        this.emit('down');
         cb();
       },
     );

src/worker/worker.ts

@@ -9,7 +9,6 @@
 
 import { Ticker } from '../ticker/ticker';
 import { ICallback } from '../../types';
-import { events } from '../events/events';
 import { PowerSwitch } from '../power-switch/power-switch';
 import { WorkerError } from './errors';
 
@@ -63,7 +62,7 @@ export abstract class Worker {
       const powerManager = this.getPowerManager();
       powerManager.goingDown();
       const ticker = this.getTicker();
-      ticker.on(events.DOWN, () => {
+      ticker.on('down', () => {
         powerManager.commit();
         cb();
       });

types/event/event.ts

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c)
+ * Weyoss <weyoss@protonmail.com>
+ * https://github.com/weyoss
+ *
+ * This source code is licensed under the MIT license found in the LICENSE file
+ * in the root directory of this source tree.
+ */
+
+export type TEvent = {
+  error: (err: Error) => void;
+  next: () => void;
+  up: () => void;
+  down: () => void;
+  goingUp: () => void;
+  goingDown: () => void;
+  tick: () => void;
+};

types/event/index.ts

@@ -0,0 +1,10 @@
+/*
+ * Copyright (c)
+ * Weyoss <weyoss@protonmail.com>
+ * https://github.com/weyoss
+ *
+ * This source code is licensed under the MIT license found in the LICENSE file
+ * in the root directory of this source tree.
+ */
+
+export * from './event';

types/index.ts

@@ -10,3 +10,4 @@
 export * from './common';
 export * from './redis';
 export * from './logger';
+export * from './event';