add triggering unhandled promise rejection events, fixes #205

CHANGELOG.md

@@ -4,6 +4,7 @@
   - `.forEach` method to iterable DOM collections ([#329](https://github.com/zloirock/core-js/issues/329))
   - `Symbol#description` ([stage 1 proposal](https://tc39.github.io/proposal-Symbol-description/))
   - `String#replaceAll` ([stage 1 proposal](https://github.com/psmarshall/string-replace-all-proposal))
+  - Triggering unhandled `Promise` rejection events (instead of only global handlers) [#205](https://github.com/zloirock/core-js/issues/205)
 - Removed obsolete features:
   - `Error.isError` (withdrawn)
   - `System.global` (replaced by `global`)

README.md

@@ -801,6 +801,9 @@ setTimeout(() => promise.catch(() => {}), 1e3);
 ```
 In a browser on rejection, by default, you will see notify in the console, or you can add a custom handler and a handler on handling unhandled, [*example*](http://goo.gl/Wozskl):
 ```js
+window.addEventListener('unhandledrejection', e => console.log('unhandled', e.reason, e.promise));
+window.addEventListener('rejectionhandled', e => console.log('handled', e.reason, e.promise));
+// or
 window.onunhandledrejection = e => console.log('unhandled', e.reason, e.promise);
 window.onrejectionhandled = e => console.log('handled', e.reason, e.promise);
 

modules/es.promise.js

@@ -18,11 +18,15 @@ var hostReportErrors = require('./_host-report-errors');
 var PROMISE = 'Promise';
 var TypeError = global.TypeError;
 var process = global.process;
+var document = global.document;
 var $Promise = global[PROMISE];
 var isNode = classof(process) == 'process';
 var empty = function () { /* empty */ };
 var Internal, newGenericPromiseCapability, OwnPromiseCapability, Wrapper;
 var newPromiseCapability = newGenericPromiseCapability = newPromiseCapabilityModule.f;
+var DISPATCH_EVENT = !!(document && document.createEvent && global.dispatchEvent);
+var UNHANDLED_REJECTION = 'unhandledrejection';
+var REJECTION_HANDLED = 'rejectionhandled';
 
 var USE_NATIVE = !!function () {
   try {
@@ -87,18 +91,28 @@ var notify = function (promise, isReject) {
     if (isReject && !promise._h) onUnhandled(promise);
   });
 };
+var dispatchEvent = function (name, promise, reason) {
+  var event, handler;
+  if (DISPATCH_EVENT) {
+    event = document.createEvent('Event');
+    event.promise = promise;
+    event.reason = reason;
+    event.initEvent(name, false, true);
+    global.dispatchEvent(event);
+  } else event = { promise: promise, reason: reason };
+  if (handler = global['on' + name]) handler(event);
+  else if (name === UNHANDLED_REJECTION) hostReportErrors('Unhandled promise rejection', reason);
+};
 var onUnhandled = function (promise) {
   task.call(global, function () {
     var value = promise._v;
     var unhandled = isUnhandled(promise);
-    var result, handler;
+    var result;
     if (unhandled) {
       result = perform(function () {
         if (isNode) {
           process.emit('unhandledRejection', value, promise);
-        } else if (handler = global.onunhandledrejection) {
-          handler({ promise: promise, reason: value });
-        } else hostReportErrors('Unhandled promise rejection', value);
+        } else dispatchEvent(UNHANDLED_REJECTION, promise, value);
       });
       // Browsers should not trigger `rejectionHandled` event if it was handled here, NodeJS - should
       promise._h = isNode || isUnhandled(promise) ? 2 : 1;
@@ -111,12 +125,9 @@ var isUnhandled = function (promise) {
 };
 var onHandleUnhandled = function (promise) {
   task.call(global, function () {
-    var handler;
     if (isNode) {
       process.emit('rejectionHandled', promise);
-    } else if (handler = global.onrejectionhandled) {
-      handler({ promise: promise, reason: promise._v });
-    }
+    } else dispatchEvent(REJECTION_HANDLED, promise, promise._v);
   });
 };
 var $reject = function (value) {

tests/library/es.promise.js

@@ -390,7 +390,21 @@ QUnit.test('Unhandled rejection tracking', assert => {
     process.on('unhandledRejection', onunhandledrejection);
     process.on('rejectionHandled', onrejectionhandled);
   } else {
-    assert.expect(4);
+    if (GLOBAL.addEventListener) {
+      assert.expect(8);
+      function onunhandledrejection(it) {
+        assert.same(it.promise, $promise, 'addEventListener(unhandledrejection), promise');
+        assert.same(it.reason, 42, 'addEventListener(unhandledrejection), reason');
+        GLOBAL.removeEventListener('unhandledrejection', onunhandledrejection);
+      }
+      GLOBAL.addEventListener('rejectionhandled', onunhandledrejection);
+      function onrejectionhandled(it) {
+        assert.same(it.promise, $promise, 'addEventListener(rejectionhandled), promise');
+        assert.same(it.reason, 42, 'addEventListener(rejectionhandled), reason');
+        GLOBAL.removeEventListener('rejectionhandled', onrejectionhandled);
+      }
+      GLOBAL.addEventListener('rejectionhandled', onrejectionhandled);
+    } else assert.expect(4);
     GLOBAL.onunhandledrejection = function (it) {
       assert.same(it.promise, $promise, 'onunhandledrejection, promise');
       assert.same(it.reason, 42, 'onunhandledrejection, reason');

tests/tests/es.promise.js

@@ -414,7 +414,21 @@ QUnit.test('Unhandled rejection tracking', assert => {
     process.on('unhandledRejection', onunhandledrejection);
     process.on('rejectionHandled', onrejectionhandled);
   } else {
-    assert.expect(4);
+    if (GLOBAL.addEventListener) {
+      assert.expect(8);
+      function onunhandledrejection(it) {
+        assert.same(it.promise, $promise, 'addEventListener(unhandledrejection), promise');
+        assert.same(it.reason, 42, 'addEventListener(unhandledrejection), reason');
+        GLOBAL.removeEventListener('unhandledrejection', onunhandledrejection);
+      }
+      GLOBAL.addEventListener('rejectionhandled', onunhandledrejection);
+      function onrejectionhandled(it) {
+        assert.same(it.promise, $promise, 'addEventListener(rejectionhandled), promise');
+        assert.same(it.reason, 42, 'addEventListener(rejectionhandled), reason');
+        GLOBAL.removeEventListener('rejectionhandled', onrejectionhandled);
+      }
+      GLOBAL.addEventListener('rejectionhandled', onrejectionhandled);
+    } else assert.expect(4);
     GLOBAL.onunhandledrejection = function (it) {
       assert.same(it.promise, $promise, 'onunhandledrejection, promise');
       assert.same(it.reason, 42, 'onunhandledrejection, reason');