PromiseRejectionEvent()

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PromiseRejectionEvent() constructor returns a newly created PromiseRejectionEvent , which represents events fired when a JavaScript Promise is rejected. With promise rejection events, it becomes possible to detect and report promises which fail and whose failures go unnoticed. It also becomes easier to write a global handler for errors.

There are two types of PromiseRejectionEvent : unhandledrejection is sent by the JavaScript runtime when a promise is rejected but the rejection goes unhandled. A rejectionhandled event is emitted if a promise is rejected but the rejection is caught by a rejection handler..

句法

promiseRejectionEvent = PromiseRejectionEvent(type, options);

参数

PromiseRejectionEvent() constructor also inherits parameters from Event() .

type

A string representing the name of the type of the


								PromiseRejectionEvent

. This is case-sensitive and should be one of


								
									"rejectionhandled"


								
									"unhandledrejection"

, to match the event names of the possible (non-synthetic)


									PromiseRejectionEvent

events that user agents can actually fire).

选项


									对象

specifying details about the rejection which occurred:

promise: Promise that was rejected.
reason: Any value or 对象 which represents the reason the promise was rejected. This can be anything from a numeric error code to an error DOMString to an object which contains detailed information describing the situation resulting in the promise being rejected.

返回值

新的 PromiseRejectionEvent configured as specified by the parameters.

范例

This example creates a new unhandledrejection event for the promise myPromise with the reason being the string "My house is on fire". The reason could just as easily be a number, or even an object with detailed information including the home address, how serious the fire is, and the phone number of an emergency contact who should be notified.

let myRejectionEvent = new PromiseRejectionEvent("unhandledrejection", {
  promise : myPromise,
  reason : "My house is on fire"
});

规范

规范	状态	注释
HTML 实时标准 The definition of 'the PromiseRejectionEvent interface' in that specification.	实时标准	初始定义。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`PromiseRejectionEvent()` 构造函数	Chrome 49	Edge ≤79	Firefox 69 69 Disabled ). To change preferences in Firefox, visit	IE No	Opera 36	Safari 11	WebView Android 49	Chrome Android 49	Firefox Android 68	Opera Android 36	Safari iOS 11.3	Samsung Internet Android 5.0

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句法

参数

返回值

范例

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浏览器兼容性

图例

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