🎨 optimize code (#2924)

src/sandbox/patchers/windowListener.ts

@@ -1,4 +1,3 @@
-/* eslint-disable no-param-reassign */
 /**
  * @author Kuitos
  * @since 2019-04-11
@@ -17,61 +16,58 @@ type ListenerMapObject = {
 
 const DEFAULT_OPTIONS: AddEventListenerOptions = { capture: false, once: false, passive: false };
 
-// 移除cacheListener
+const normalizeOptions = (rawOptions?: boolean | AddEventListenerOptions): AddEventListenerOptions => {
+  if (typeof rawOptions === 'object') {
+    return rawOptions ?? DEFAULT_OPTIONS;
+  }
+  return { capture: !!rawOptions, once: false, passive: false };
+};
+
+const findListenerIndex = (
+  listeners: ListenerMapObject[],
+  rawListener: EventListenerOrEventListenerObject,
+  options: AddEventListenerOptions,
+): number =>
+  listeners.findIndex((item) => item.rawListener === rawListener && item.options.capture === options.capture);
+
 const removeCacheListener = (
   listenerMap: Map<string, ListenerMapObject[]>,
   type: string,
   rawListener: EventListenerOrEventListenerObject,
   rawOptions?: boolean | AddEventListenerOptions,
 ): ListenerMapObject => {
-  // 处理 options，确保它是一个对象
-  let options = typeof rawOptions === 'object' ? rawOptions : { capture: !!rawOptions };
-  // 如果 options 为 null，使用默认值
-  options = options ?? DEFAULT_OPTIONS;
-
+  const options = normalizeOptions(rawOptions);
   const cachedTypeListeners = listenerMap.get(type) || [];
-  // listener和capture/useCapture都相同，认为是同一个监听
-  // https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/removeEventListener
-  const findIndex = cachedTypeListeners.findIndex(
-    (item) => item.rawListener === rawListener && item.options.capture == options.capture,
-  );
+
+  const findIndex = findListenerIndex(cachedTypeListeners, rawListener, options);
   if (findIndex > -1) {
-    const cacheListener = cachedTypeListeners[findIndex];
-    cachedTypeListeners.splice(findIndex, 1);
-    return cacheListener;
+    return cachedTypeListeners.splice(findIndex, 1)[0];
   }
 
-  // 返回原始listener和options
   return { listener: rawListener, rawListener, options };
 };
 
-// 添加监听构造一个cacheListener对象，考虑到多次添加同一个监听和once的情况
 const addCacheListener = (
   listenerMap: Map<string, ListenerMapObject[]>,
   type: string,
   rawListener: EventListenerOrEventListenerObject,
   rawOptions?: boolean | AddEventListenerOptions,
 ): ListenerMapObject | undefined => {
-  // 处理 options，确保它是一个对象
-  let options = typeof rawOptions === 'object' ? rawOptions : { capture: !!rawOptions };
-  // 如果 options 为 null，使用默认值
-  options = options ?? DEFAULT_OPTIONS;
-
+  const options = normalizeOptions(rawOptions);
   const cachedTypeListeners = listenerMap.get(type) || [];
-  // listener和capture/useCapture都相同，认为是同一个监听
-  // https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener
-  const findIndex = cachedTypeListeners.findIndex(
-    (item) => item.rawListener === rawListener && item.options.capture == options.capture,
-  );
-  // 如果事件已经添加到了target的event listeners 列表中，直接返回不需要添加第二次
+
+  const findIndex = findListenerIndex(cachedTypeListeners, rawListener, options);
+  // avoid duplicated listener in the listener list
   if (findIndex > -1) return;
 
   let listener: EventListenerOrEventListenerObject = rawListener;
-  if (options.once)
+  if (options.once) {
     listener = (event: Event) => {
       (rawListener as EventListener)(event);
       removeCacheListener(listenerMap, type, rawListener, options);
     };
+  }
+
   const cacheListener = { listener, options, rawListener };
   listenerMap.set(type, [...cachedTypeListeners, cacheListener]);
   return cacheListener;
@@ -86,10 +82,9 @@ export default function patch(global: WindowProxy) {
     rawOptions?: boolean | AddEventListenerOptions,
   ) => {
     const addListener = addCacheListener(listenerMap, type, rawListener, rawOptions);
-    // 如果返回空，则代表事件已经添加过了，不需要重复添加
+
     if (!addListener) return;
-    const { listener, options } = addListener;
-    return rawAddEventListener.call(window, type, listener, options);
+    return rawAddEventListener.call(global, type, addListener.listener, addListener.options);
   };
 
   global.removeEventListener = (
@@ -98,18 +93,18 @@ export default function patch(global: WindowProxy) {
     rawOptions?: boolean | AddEventListenerOptions,
   ) => {
     const { listener, options } = removeCacheListener(listenerMap, type, rawListener, rawOptions);
-    return rawRemoveEventListener.call(window, type, listener, options);
+    return rawRemoveEventListener.call(global, type, listener, options);
   };
 
   return function free() {
-    listenerMap.forEach((listeners, type) =>
-      [...listeners].forEach(({ rawListener, options }) => global.removeEventListener(type, rawListener, options)),
-    );
-    // 清空listenerMap，避免listenerMap中还存有listener导致内存泄漏
+    listenerMap.forEach((listeners, type) => {
+      listeners.forEach(({ rawListener, options }) => {
+        global.removeEventListener(type, rawListener, options);
+      });
+    });
     listenerMap.clear();
     global.addEventListener = rawAddEventListener;
     global.removeEventListener = rawRemoveEventListener;
-
     return noop;
   };
 }