puffcocos · puffcocos · Apr 11, 2023 · Apr 11, 2023 · Apr 11, 2023
diff --git a/client/src/event-bus/bus.spec.ts b/client/src/event-bus/bus.spec.ts
@@ -0,0 +1,39 @@
+import EventBus from './bus'
+
+describe('EventBus (class)', () => {
+  it('should subscribe event', () => {
+    const eventBus = EventBus.getInstance()
+
+    let result = null
+    const unsubscribe = eventBus.on('subscribe-test', () => (result = 'success'))
+    eventBus.emit('subscribe-test')
+
+    expect(result).toBe('success')
+
+    unsubscribe()
+  })
+
+  it('should unsubscribe event', () => {
+    const eventBus = EventBus.getInstance()
+
+    let result = null
+    const unsubscribe = eventBus.on('subscribe-test', () => (result = 'success'))
+    unsubscribe()
+    eventBus.emit('subscribe-test')
+
+    expect(result).toBe(null)
+
+    unsubscribe()
+  })
+
+  it('should subscribe once', () => {
+    const eventBus = EventBus.getInstance()
+
+    let result = null
+    eventBus.once('subscribe-test', (flag: string) => (result = flag))
+    eventBus.emit('subscribe-test', 'success')
+    eventBus.emit('subscribe-test', 'fail')
+
+    expect(result).toBe('success')
+  })
+})
diff --git a/client/src/event-bus/bus.ts b/client/src/event-bus/bus.ts
@@ -0,0 +1,63 @@
+type Key = string
+type Handler = (...payload: any[]) => void
+type UnsubscribeFunc = () => void
+
+interface Bus {
+  on(key: Key, handler: Handler): UnsubscribeFunc
+  off(key: Key, handler: Handler): void
+  emit(key: Key, ...payload: Parameters<Handler>): void
+  once(key: Key, handler: Handler): void
+}
+
+export default class EventBus implements Bus {
+  #record: Map<Key, Handler[]>
+  static #instance: EventBus
+
+  constructor() {
+    this.#record = new Map()
+  }
+
+  get record() {
+    return this.#record
+  }
+
+  public static getInstance() {
+    if (!this.#instance) {
+      this.#instance = new EventBus()
+    }
+
+    return this.#instance
+  }
+
+  public on(key: Key, handler: Handler) {
+    if (!this.#record.has(key)) {
+      this.#record.set(key, [])
+    }
+
+    const queue = this.#record.get(key)
+    queue?.push(handler)
+
+    return () => {
+      this.off(key, handler)
+    }
+  }
+
+  public off(key: Key, handler: Handler) {
+    const index = this.#record.get(key)?.indexOf(handler) ?? -1
+    this.#record.get(key)?.splice(index >>> 0, 1)
+  }
+
+  public emit(key: Key, ...payload: any[]) {
+    const handlers = this.#record.get(key)
+    handlers?.forEach((handler) => handler(...payload))
+  }
+
+  public once(key: Key, handler: Handler) {
+    const handleOnce = (...payload: any[]) => {
+      handler(...payload)
+      this.off(key, handleOnce)
+    }
+
+    this.on(key, handleOnce)
+  }
+}
diff --git a/client/src/event-bus/index.ts b/client/src/event-bus/index.ts
@@ -0,0 +1 @@
+export { default as EventBus } from './bus'