This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
The reason read-only property of the PromiseRejection returns the rejection reason for the Promise that the current notification is about. Although the reason can be undefined, it is generally an Error object, like in exception handling.
Syntax
var myPromiseRejectionReason = myPromiseRejection.reason;
Value
A DOMString that represents the promise's rejection reason.
Example
var myPromiseRejection = new PromiseRejection(); var myPromiseRejectionReason = myPromiseRejection.reason;
Specifications
| Specification | Status | Comment | 
|---|---|---|
| Unhandled Rejection Tracking Browser Events The definition of 'PromiseRejectionEvent' in that specification. | Editor's Draft | Initial definition. | 
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) | 
|---|---|---|---|---|---|
| Basic support | 49.0 | 45.0 (45.0) | No support | ? | No support | 
| Feature | Android | Android Webview | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android | 
|---|---|---|---|---|---|---|---|---|
| Basic support | No support | 49.0 | 45.0 (45.0) | (Yes) | No support | ? | No support | 49.0 |