Create intermediaries for global objects

This is in order to reduce memory leaks in JSDOM as it shares prototypes between environments Those objects are: - Event - EventTarget - XMLHttpRequestEventTarget - HTMLCanvasElement
angular · Jun 26, 2018 · 043f18d · 043f18d
1 parent 0a2f6ff
commit 043f18d
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Showing 2 changed files with 39 additions and 1 deletion.
diff --git a/lib/browser/browser.ts b/lib/browser/browser.ts
@@ -12,7 +12,7 @@
 
 import {findEventTasks} from '../common/events';
 import {patchTimer} from '../common/timers';
-import {bindArguments, patchClass, patchMacroTask, patchMethod, patchOnProperties, patchPrototype, scheduleMacroTaskWithCurrentZone, ZONE_SYMBOL_ADD_EVENT_LISTENER, ZONE_SYMBOL_REMOVE_EVENT_LISTENER, zoneSymbol} from '../common/utils';
+import {bindArguments, patchClass, patchMacroTask, patchMethod, patchOnProperties, patchPrototype, scheduleMacroTaskWithCurrentZone, ZONE_SYMBOL_ADD_EVENT_LISTENER, ZONE_SYMBOL_REMOVE_EVENT_LISTENER, zoneSymbol, createConstructorFunctionWrapper, createShallowObjectCopy, ObjectGetPrototypeOf} from '../common/utils';
 
 import {propertyPatch} from './define-property';
 import {eventTargetPatch, patchEvent} from './event-target';
@@ -58,6 +58,15 @@ Zone.__load_patch('EventTarget', (global: any, Zone: ZoneType, api: _ZonePrivate
     (Zone as any)[SYMBOL_BLACK_LISTED_EVENTS] = global[SYMBOL_BLACK_LISTED_EVENTS];
   }
 
+  global['Event'] = createConstructorFunctionWrapper(global['Event']);
+  global['EventTarget'] = createConstructorFunctionWrapper(global['EventTarget']);
+
+  if (global['XMLHttpRequestEventTarget'] && global['XMLHttpRequestEventTarget'].prototype) {
+    const XMLHttpRequestEventTargetProtoProto = createShallowObjectCopy(ObjectGetPrototypeOf(global['XMLHttpRequestEventTarget'].prototype));
+    global['XMLHttpRequestEventTarget'] = createConstructorFunctionWrapper(global['XMLHttpRequestEventTarget']);
+    (Object as any).setPrototypeOf(global['XMLHttpRequestEventTarget'].prototype, XMLHttpRequestEventTargetProtoProto);
+  }
+
   patchEvent(global, api);
   eventTargetPatch(global, api);
   // patch XMLHttpRequestEventTarget's addEventListener/removeEventListener
@@ -78,6 +87,8 @@ Zone.__load_patch('on_property', (global: any, Zone: ZoneType, api: _ZonePrivate
 });
 
 Zone.__load_patch('canvas', (global: any) => {
+  global['HTMLCanvasElement'] = createConstructorFunctionWrapper(global['HTMLCanvasElement']);
+
   const HTMLCanvasElement = global['HTMLCanvasElement'];
   if (typeof HTMLCanvasElement !== 'undefined' && HTMLCanvasElement.prototype &&
       HTMLCanvasElement.prototype.toBlob) {

diff --git a/lib/common/utils.ts b/lib/common/utils.ts
@@ -484,3 +484,30 @@ export function isIEOrEdge() {
   } catch (error) {
   }
 }
+
+export function createShallowObjectCopy(obj: Object) {
+  const wrapper = ObjectCreate(obj);
+
+  Object.getOwnPropertyNames(obj).forEach((key: string) => {
+    const desc = Object.getOwnPropertyDescriptor(obj, key);
+    if (desc) {
+      Object.defineProperty(wrapper, key, desc);
+    }
+  });
+
+  return wrapper;
+}
+
+export function createConstructorFunctionWrapper(fn: Function | ObjectConstructor) {
+  if (typeof fn !== 'function') {
+    return fn;
+  }
+
+  const wrappedFn = function(...args: any[]) {
+    return new (fn as any)(...args);
+  }
+
+  wrappedFn.prototype = createShallowObjectCopy(fn.prototype);
+
+  return wrappedFn;
+}