feat: add offListener method

Author: sanyuan0704

README.md

@@ -121,6 +121,15 @@ parentPort.onMessage('ack', payload => {
     path: ' /',
   });
 });
+
+// 4. If you want to remove some listeners
+const handleAck = (payload) => {
+  console.log('[parent] [syn]');
+};
+parentPort.onMessage('ack', handleAck);
+parentPort.offListener('ack', handleAck);
+// Note: if the second param of `offListener` is omitted, all listeners will be removed.
+parentPort.offMessage('ack');
 ```
 
 3. Child process implementation:
@@ -154,6 +163,15 @@ childPort.onMessage('syn', payload => {
 childPort.onMessage('body', payload => {
   console.log('[child] [body]', JSON.stringify(payload));
 });
+
+// 4. If you want to remove some listeners by `offMessage`
+const handleSyn = (payload) => {
+  console.log('[child] [syn]');
+};
+childPort.onMessage('syn', handleSyn);
+childPort.offListener('syn', handleSyn);
+// Note: if the second param of `offListener` is omitted, all listeners will be removed.
+childPort.offMessage('syn');
 ```
 
 ## 📖 Basic Concepts

src/index.ts

@@ -116,6 +116,10 @@ interface Port<T extends MessageDefinition, D extends Direction<T>> {
     t: U,
     handler: Callback<[Payload<T, ReverseDirection<T, D>, U>]>,
   ): void;
+  offListener<U extends keyof T[ReverseDirection<T, D>]>(
+    t: U,
+    handler?: Callback<[Payload<T, ReverseDirection<T, D>, U>]>,
+  ): void;
 }
 
 export type EnsureString<T> = T extends string ? T : never;
@@ -258,6 +262,20 @@ export class Unport<
     this.handlers[t].push(handler);
   };
 
+  public offListener: Port<T, InferDirectionByPort<T, U>>['offListener'] = (t, handler) => {
+    if (!this.handlers[t]) {
+      return;
+    }
+    if (handler) {
+      this.handlers[t] = this.handlers[t].filter(h => h !== handler);
+      if (this.handlers[t].length === 0) {
+        delete this.handlers[t];
+      }
+    } else {
+      delete this.handlers[t];
+    }
+  };
+
   public destroy() {
     this.handlers = {};
     this.channel?.destroy && this.channel.destroy();