The read-only PromiseRejection property reason read-only property is any JavaScript value or Object which provides the reason passed into Promise.reject(). This in theory provides information about why the promise was rejected.
reason = PromiseRejectionEvent.reason
A value or object which provides information you can use to understand why the promise was rejected. This could be anything from an error code to an object with text, links, and whatever else you might wish to include.
window.onunhandledrejection = function(e) {
console.log(e.reason);
} | Specification | Status | Comment |
|---|---|---|
| HTML Living Standard The definition of 'PromiseRejectionEvent.reason' in that specification. | Living Standard | Initial definition. |
| Desktop | ||||||
|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | |
| Basic support | 49 | ? | No
|
No | No | No |
| Mobile | |||||||
|---|---|---|---|---|---|---|---|
| Android webview | Chrome for Android | Edge Mobile | Firefox for Android | Opera for Android | iOS Safari | Samsung Internet | |
| Basic support | ? | No | ? | No
|
No | No | ? |
© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/PromiseRejectionEvent/reason