feat(jest-message-util): add support for AggregateError

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - `[jest-cli, jest-config, @jest/core, jest-haste-map, @jest/reporters, jest-runner, jest-runtime, @jest/types]` Add `workerThreads` configuration option to allow using [worker threads](https://nodejs.org/dist/latest/docs/api/worker_threads.html) for parallelization ([#13939](https://github.com/facebook/jest/pull/13939))
 - `[jest-worker]` Add `start` method to worker farms ([#13937](https://github.com/facebook/jest/pull/13937))
+- `[jest-message-util]` Add support for [AggregateErrors](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/AggregateError) ([#13946](https://github.com/facebook/jest/pull/13946))
 
 ### Fixes
 

packages/jest-message-util/src/__tests__/__snapshots__/messages.test.ts.snap

@@ -127,3 +127,22 @@ exports[`should return the error cause if there is one 1`] = `
 
 "
 `;
+
+exports[`should return the inner errors of an AggregateError 1`] = `
+"  <bold>● </intensity>Test suite failed to run
+
+    AggregateError:
+
+      <dim>at Object.<anonymous> (</intensity>packages/jest-message-util/src/__tests__/messages.test.ts<dim>:439:22)</intensity>
+
+    Errors contained in AggregateError:
+     Err 1
+
+          <dim>at Object.<anonymous> (</intensity>packages/jest-message-util/src/__tests__/messages.test.ts<dim>:440:7)</intensity>
+
+     Err 2
+
+          <dim>at Object.<anonymous> (</intensity>packages/jest-message-util/src/__tests__/messages.test.ts<dim>:441:7)</intensity>
+
+"
+`;

packages/jest-message-util/src/__tests__/messages.test.ts

@@ -431,3 +431,25 @@ it('should return the error cause if there is one', () => {
   );
   expect(message).toMatchSnapshot();
 });
+
+it('should return the inner errors of an AggregateError', () => {
+  // TODO remove this if when the lowest supported Node version is 15.0.0
+  // See https://github.com/nodejs/node/blob/main/doc/changelogs/CHANGELOG_V15.md#v8-86---35415
+  if (AggregateError) {
+    const aggError = new AggregateError([
+      new Error('Err 1'),
+      new Error('Err 2'),
+    ]);
+    const message = formatExecError(
+      aggError,
+      {
+        rootDir: '',
+        testMatch: [],
+      },
+      {
+        noStackTrace: false,
+      },
+    );
+    expect(message).toMatchSnapshot();
+  }
+});

packages/jest-message-util/src/index.ts

@@ -137,6 +137,7 @@ export const formatExecError = (
 
   let message, stack;
   let cause = '';
+  const subErrors = [];
 
   if (typeof error === 'string' || !error) {
     error || (error = 'EMPTY ERROR');
@@ -172,6 +173,20 @@ export const formatExecError = (
         cause += `${prefix}${formatted}`;
       }
     }
+    if ('errors' in error && Array.isArray(error.errors)) {
+      for (const subError of error.errors) {
+        subErrors.push(
+          formatExecError(
+            subError,
+            config,
+            options,
+            testPath,
+            reuseMessage,
+            true,
+          ),
+        );
+      }
+    }
   }
   if (cause !== '') {
     cause = indentAllLines(cause);
@@ -210,8 +225,14 @@ export const formatExecError = (
     messageToUse = `${EXEC_ERROR_MESSAGE}\n\n${message}`;
   }
   const title = noTitle ? '' : `${TITLE_INDENT + TITLE_BULLET}`;
+  const subErrorStr =
+    subErrors.length > 0
+      ? indentAllLines(
+          `\n\nErrors contained in AggregateError:\n${subErrors.join('\n')}`,
+        )
+      : '';
 
-  return `${title + messageToUse + stack + cause}\n`;
+  return `${title + messageToUse + stack + cause + subErrorStr}\n`;
 };
 
 const removeInternalStackEntries = (