fix(event): fix #836, handle event callback call removeEventListener case

Author: JiaLiPassion

lib/common/events.ts

@@ -62,8 +62,20 @@ export function patchEventTarget(
     const tasks = target[zoneSymbolEventNames[event.type][FALSE_STR]];
     if (tasks) {
       // invoke all tasks which attached to current target with given event.type and capture = false
-      for (let i = 0; i < tasks.length; i++) {
-        invokeTask(tasks[i], target, event);
+      if (tasks.length === 1) {
+        invokeTask(tasks[0], target, event);
+      } else {
+        // https://github.com/angular/zone.js/issues/836
+        // copy the tasks array before invoke, to avoid
+        // the callback will remove itself or other listener
+        const copyTasks = tasks.slice();
+        for (let i = 0; i < copyTasks.length; i++) {
+          const task = copyTasks[i];
+          if (tasks.indexOf(task) === -1) {
+            continue;
+          }
+          invokeTask(task, target, event);
+        }
       }
     }
   };
@@ -74,8 +86,21 @@ export function patchEventTarget(
 
     const tasks = target[zoneSymbolEventNames[event.type][TRUE_STR]];
     if (tasks) {
-      for (let i = 0; i < tasks.length; i++) {
-        invokeTask(tasks[i], target, event);
+      // invoke all tasks which attached to current target with given event.type and capture = false
+      if (tasks.length === 1) {
+        invokeTask(tasks[0], target, event);
+      } else {
+        // https://github.com/angular/zone.js/issues/836
+        // copy the tasks array before invoke, to avoid
+        // the callback will remove itself or other listener
+        const copyTasks = tasks.slice();
+        for (let i = 0; i < copyTasks.length; i++) {
+          const task = copyTasks[i];
+          if (tasks.indexOf(task) === -1) {
+            continue;
+          }
+          invokeTask(task, target, event);
+        }
       }
     }
   };