Add cause property with the original error to RequestError (#2327)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

documentation/8-errors.md

@@ -19,8 +19,9 @@ All Got errors contain various metadata, such as:
 
 Read the article [here](async-stack-traces.md).
 
-**Note:**
+> [!NOTE]
 > - The error codes may differ when the root error has a `code` property set.
+> - The root error will be propagated as is via the [`cause`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/cause) property.
 
 ### `RequestError`
 
@@ -62,8 +63,8 @@ A request is successful when the status code of the final request is `2xx` or `3
 
 When [following redirects](2-options.md#followredirect), a request is successful **only** when the status code of the final request is `2xx`.
 
-**Note:**
-> - `304` responses are always considered successful.
+> [!NOTE]
+> `304` responses are always considered successful.
 
 ### `MaxRedirectsError`
 
@@ -73,8 +74,8 @@ When the server redirects you more than ten times. Includes a `response` propert
 
 ### `UnsupportedProtocolError`
 
-**Note:**
-> - This error is not public.
+> [!NOTE]
+> This error is not public.
 
 **Code: `ERR_UNSUPPORTED_PROTOCOL`**
 

source/core/errors.ts

@@ -27,7 +27,7 @@ export class RequestError<T = unknown> extends Error {
 	readonly timings?: Timings;
 
 	constructor(message: string, error: Partial<Error & {code?: string}>, self: Request | Options) {
-		super(message);
+		super(message, {cause: error});
 		Error.captureStackTrace(this, this.constructor);
 
 		this.name = 'RequestError';

test/error.ts

@@ -4,6 +4,7 @@ import net from 'node:net';
 import http from 'node:http';
 import stream from 'node:stream';
 import {pipeline as streamPipeline} from 'node:stream/promises';
+import {Agent} from 'node:https';
 import test from 'ava';
 import getStream from 'get-stream';
 import is from '@sindresorhus/is';
@@ -359,6 +360,28 @@ test.skip('the old stacktrace is recovered', async t => {
 	t.not(error?.stack!.indexOf('at get'), error?.stack!.lastIndexOf('at get'));
 });
 
+test('should wrap got cause', async t => {
+	const error = await t.throwsAsync<RequestError>(got('https://github.com', {retry: {limit: 0}, timeout: {request: 1}}));
+	const cause = error?.cause as TimeoutError;
+	t.is(error?.code, cause.code);
+	t.is(error?.message, cause.message);
+});
+
+test('should wrap non-got cause', async t => {
+	class SocksProxyAgent extends Agent {
+		createConnection() {
+			throw new SocksClientError('oh no');
+		}
+	}
+	class SocksClientError extends Error {}
+	const error = await t.throwsAsync<RequestError>(got('https://github.com', {retry: {limit: 0}, timeout: {read: 1}, agent: {https: new SocksProxyAgent()}}));
+	const cause = error?.cause as Error;
+	t.is(error?.code, 'ERR_GOT_REQUEST_ERROR');
+	t.is(error?.message, cause.message);
+	t.is(error?.message, 'oh no');
+	t.assert(cause instanceof SocksClientError);
+});
+
 test.serial('custom stack trace', withServer, async (t, _server, got) => {
 	// eslint-disable-next-line @typescript-eslint/naming-convention
 	const ErrorCaptureStackTrace = Error.captureStackTrace;