Preventing duplicate event listener registrations (#554)

* feat: prevent duplicate registration

* feat: add defensive code

* feat: delete set value

* modify: defensive code 'throw error > console.warn'

* modify: defensive code > use 'eventName'

* modfiy: delete getTime

* modify: listeners delete key

---------

Co-authored-by: bitto-dunamu <bitto@dunamu.com>

Author: seungdeng17

modules/mixins/animate-scroll.js

@@ -171,9 +171,10 @@ const animateTopScroll = (scrollOffset, options, to, target) => {
 
   window.clearTimeout(options.data.delayTimeout);
 
-  cancelEvents.subscribe(() => {
+  const setCancel = () => {
     options.data.cancel = true;
-  });
+  };
+  cancelEvents.subscribe(setCancel);
 
   setContainer(options);
 

modules/mixins/passive-event-listeners.js

@@ -4,6 +4,16 @@
  * to wait for the listener to return.
  */
 export const addPassiveEventListener = (target, eventName, listener) => {
+  let listenerName = listener.name;
+  if (!listenerName) {
+    listenerName = eventName;
+    console.warn('Listener must be a named function.');
+  }
+
+  if (!attachedListeners.has(eventName)) attachedListeners.set(eventName, new Set());
+  const listeners = attachedListeners.get(eventName);
+  if (listeners.has(listenerName)) return;
+
   const supportsPassiveOption = (() => {
     let supportsPassiveOption = false;
     try {
@@ -17,9 +27,12 @@ export const addPassiveEventListener = (target, eventName, listener) => {
     return supportsPassiveOption;
   })();
   target.addEventListener(eventName, listener, supportsPassiveOption ? { passive: true } : false);
+  listeners.add(listenerName);
 };
 
 export const removePassiveEventListener = (target, eventName, listener) => {
   target.removeEventListener(eventName, listener);
+  attachedListeners.get(eventName).delete(listener.name || eventName);
 }
 
+const attachedListeners = new Map();