feat(zone.js): add a zone config to allow user disable wrapping uncaught promise rejection

packages/zone.js/lib/common/promise.ts

@@ -20,6 +20,8 @@ Zone.__load_patch('ZoneAwarePromise', (global: any, Zone: ZoneType, api: _ZonePr
 
   const __symbol__ = api.symbol;
   const _uncaughtPromiseErrors: UncaughtPromiseError[] = [];
+  const isDisableWrappingUncaughtPromiseRejection =
+      global[__symbol__('DISABLE_WRAPPING_UNCAUGHT_PROMISE_REJECTION')] === true;
   const symbolPromise = __symbol__('Promise');
   const symbolThen = __symbol__('then');
   const creationTrace = '__creationTrace__';
@@ -41,13 +43,11 @@ Zone.__load_patch('ZoneAwarePromise', (global: any, Zone: ZoneType, api: _ZonePr
 
   api.microtaskDrainDone = () => {
     while (_uncaughtPromiseErrors.length) {
-      while (_uncaughtPromiseErrors.length) {
-        const uncaughtPromiseError: UncaughtPromiseError = _uncaughtPromiseErrors.shift() !;
-        try {
-          uncaughtPromiseError.zone.runGuarded(() => { throw uncaughtPromiseError; });
-        } catch (error) {
-          handleUnhandledRejection(error);
-        }
+      const uncaughtPromiseError: UncaughtPromiseError = _uncaughtPromiseErrors.shift() !;
+      try {
+        uncaughtPromiseError.zone.runGuarded(() => { throw uncaughtPromiseError; });
+      } catch (error) {
+        handleUnhandledRejection(error);
       }
     }
   };
@@ -58,7 +58,7 @@ Zone.__load_patch('ZoneAwarePromise', (global: any, Zone: ZoneType, api: _ZonePr
     api.onUnhandledError(e);
     try {
       const handler = (Zone as any)[UNHANDLED_PROMISE_REJECTION_HANDLER_SYMBOL];
-      if (handler && typeof handler === 'function') {
+      if (typeof handler === 'function') {
         handler.call(this, e);
       }
     } catch (err) {
@@ -176,20 +176,28 @@ Zone.__load_patch('ZoneAwarePromise', (global: any, Zone: ZoneType, api: _ZonePr
         }
         if (queue.length == 0 && state == REJECTED) {
           (promise as any)[symbolState] = REJECTED_NO_CATCH;
-          try {
-            // try to print more readable error log
-            throw new Error(
-                'Uncaught (in promise): ' + readableObjectToString(value) +
-                (value && value.stack ? '\n' + value.stack : ''));
-          } catch (err) {
-            const error: UncaughtPromiseError = err;
-            error.rejection = value;
-            error.promise = promise;
-            error.zone = Zone.current;
-            error.task = Zone.currentTask !;
-            _uncaughtPromiseErrors.push(error);
-            api.scheduleMicroTask();  // to make sure that it is running
+          let uncaughtPromiseError = value;
+          if (!isDisableWrappingUncaughtPromiseRejection) {
+            // If disable wrapping uncaught promise reject
+            // and the rejected value is an Error object,
+            // use the value instead of wrapping it.
+            try {
+              // Here we throws a new Error to print more readable error log
+              // and if the value is not an error, zone.js builds an `Error`
+              // Object here to attach the stack information.
+              throw new Error(
+                  'Uncaught (in promise): ' + readableObjectToString(value) +
+                  (value && value.stack ? '\n' + value.stack : ''));
+            } catch (err) {
+              uncaughtPromiseError = err;
+            }
           }
+          uncaughtPromiseError.rejection = value;
+          uncaughtPromiseError.promise = promise;
+          uncaughtPromiseError.zone = Zone.current;
+          uncaughtPromiseError.task = Zone.currentTask !;
+          _uncaughtPromiseErrors.push(uncaughtPromiseError);
+          api.scheduleMicroTask();  // to make sure that it is running
         }
       }
     }

packages/zone.js/lib/zone.configurations.api.ts

@@ -529,6 +529,17 @@ interface ZoneGlobalConfigurations {
    * The preceding code makes all scroll event listeners passive.
    */
   __zone_symbol__PASSIVE_EVENTS?: boolean;
+
+  /**
+   * Disable wrapping uncaught promise rejection.
+   *
+   * By default, `zone.js` wraps the uncaught promise rejection in a new `Error` object
+   * which contains additional information such as a value of the rejection and a stack trace.
+   *
+   * If you set `__zone_symbol__DISABLE_WRAPPING_UNCAUGHT_PROMISE_REJECTION = true;` before
+   * importing `zone.js`, `zone.js` will not wrap the uncaught promise rejection.
+   */
+  __zone_symbol__DISABLE_WRAPPING_UNCAUGHT_PROMISE_REJECTION?: boolean;
 }
 
 /**

packages/zone.js/test/BUILD.bazel

@@ -33,6 +33,7 @@ ts_library(
         ],
         exclude = [
             "common/Error.spec.ts",
+            "common/promise-disable-wrap-uncaught-promise-rejection.spec.ts",
         ],
     ),
     deps = [
@@ -253,7 +254,10 @@ env_entry_point = ":browser-env-setup.ts"
 
 test_srcs = glob(
     ["browser/*.ts"],
-    exclude = ["browser/shadydom.spec.ts"],
+    exclude = [
+        "browser/shadydom.spec.ts",
+        "common/promise-disable-wrap-uncaught-promise-rejection.spec.ts",
+    ],
 ) + [
     "extra/cordova.spec.ts",
     "mocha-patch.spec.ts",
@@ -323,3 +327,24 @@ karma_test(
         "browser_shadydom_entry_point.ts",
     ],
 )
+
+karma_test(
+    name = "browser_disable_wrap_uncaught_promise_rejection",
+    bootstraps = {"browser_disable_wrap_uncaught_promise_rejection": [
+        "//packages/zone.js/dist:zone-testing-bundle.js",
+    ]},
+    ci = False,
+    env_deps = [
+        "//packages/zone.js/lib",
+    ],
+    env_entry_point = ":browser_disable_wrap_uncaught_promise_rejection_setup.ts",
+    env_srcs = ["browser_disable_wrap_uncaught_promise_rejection_setup.ts"],
+    test_deps = [
+        "//packages/zone.js/lib",
+    ],
+    test_entry_point = ":browser_disable_wrap_uncaught_promise_rejection_entry_point.ts",
+    test_srcs = [
+        "common/promise-disable-wrap-uncaught-promise-rejection.spec.ts",
+        "browser_disable_wrap_uncaught_promise_rejection_entry_point.ts",
+    ],
+)

packages/zone.js/test/browser_disable_wrap_uncaught_promise_rejection_entry_point.ts

@@ -0,0 +1,8 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import './common/promise-disable-wrap-uncaught-promise-rejection.spec';

packages/zone.js/test/browser_disable_wrap_uncaught_promise_rejection_setup.ts

@@ -0,0 +1,9 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+(window as any)['__zone_symbol__DISABLE_WRAPPING_UNCAUGHT_PROMISE_REJECTION'] = true;

packages/zone.js/test/common/promise-disable-wrap-uncaught-promise-rejection.spec.ts

@@ -0,0 +1,79 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+class TestRejection {
+  prop1?: string;
+  prop2?: string;
+}
+
+describe('disable wrap uncaught promise rejection', () => {
+  it('should notify Zone.onHandleError if promise is uncaught', (done) => {
+    let promiseError: Error|null = null;
+    let zone: Zone|null = null;
+    let task: Task|null = null;
+    let error: Error|null = null;
+    Zone.current
+        .fork({
+          name: 'promise-error',
+          onHandleError: (delegate: ZoneDelegate, current: Zone, target: Zone, error: any):
+                             boolean => {
+                               promiseError = error;
+                               delegate.handleError(target, error);
+                               return false;
+                             }
+        })
+        .run(() => {
+          zone = Zone.current;
+          task = Zone.currentTask;
+          error = new Error('rejectedErrorShouldBeHandled');
+          try {
+            // throw so that the stack trace is captured
+            throw error;
+          } catch (e) {
+          }
+          Promise.reject(error);
+          expect(promiseError).toBe(null);
+        });
+    setTimeout((): any => null);
+    setTimeout(() => {
+      expect(promiseError).toBe(error);
+      expect((promiseError as any)['rejection']).toBe(error);
+      expect((promiseError as any)['zone']).toBe(zone);
+      expect((promiseError as any)['task']).toBe(task);
+      done();
+    });
+  });
+
+  it('should print original information when a non-Error object is used for rejection', (done) => {
+    let promiseError: Error|null = null;
+    let rejectObj: TestRejection;
+    Zone.current
+        .fork({
+          name: 'promise-error',
+          onHandleError: (delegate: ZoneDelegate, current: Zone, target: Zone, error: any):
+                             boolean => {
+                               promiseError = error;
+                               delegate.handleError(target, error);
+                               return false;
+                             }
+        })
+        .run(() => {
+          rejectObj = new TestRejection();
+          rejectObj.prop1 = 'value1';
+          rejectObj.prop2 = 'value2';
+          (rejectObj as any).message = 'rejectMessage';
+          Promise.reject(rejectObj);
+          expect(promiseError).toBe(null);
+        });
+    setTimeout((): any => null);
+    setTimeout(() => {
+      expect(promiseError).toEqual(rejectObj as any);
+      done();
+    });
+  });
+});