aggregate-error-ponyfill

AggregateError ponyfill.

The AggregateError object represents an error when several errors need to be wrapped in a single error. It is thrown when multiple errors need to be reported by an operation, for example by Promise.any(), when all promises passed to it reject.

Install

npm install aggregate-error-ponyfill --save

Usage

import AggregateError from 'aggregate-error-ponyfill';

(async () => {
	try {
		await Promise.any([Promise.reject(new Error('some error'))]);
	} catch (e) {
		console.log(e instanceof AggregateError); // true
		console.log(e.message); // "All Promises rejected"
		console.log(e.name); // "AggregateError"
		console.log(e.errors); // [ Error: "some error" ]
	}
})();

try {
	throw new AggregateError([new Error('some error')], 'Hello');
} catch (e) {
	console.log(e instanceof AggregateError); // true
	console.log(e.message); // "Hello"
	console.log(e.name); // "AggregateError"
	console.log(e.errors); // [ Error: "some error" ]
}

You can use named export preferNative if you wish to use native implementation if it’s available. In all other cases, ponyfill will be used. Beware of caveats!

API

AggregateError(errors[, message])

Returns: AggregateError

Method description.

errors

Type: Iterable

An iterable of errors, may not actually be Error instances.

message

Type: string

An optional human-readable description of the aggregate error.

Browser support

Tested in IE11+ and all modern browsers.

It works in older IE versions such as IE9, but you can’t test for instanceof AggregateError due to proper subclassing of native classes.

Test

Test suite is taken and modified from es-shims/AggregateError polyfill.

For automated tests, run npm run test:automated (append :watch for watcher support).

License

MIT © Ivan Nikolić