feat(jest-message-util): add support for error causes

brodo · brodo · commit 87fe938befc8 · 2023-02-07T17:02:29.000+01:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ### Features
 
 - `[@jest/core]` Instrument significant lifecycle events with [`performance.mark()`](https://nodejs.org/docs/latest-v16.x/api/perf_hooks.html#performancemarkname-options) ([#13859](https://github.com/facebook/jest/pull/13859))
+- `[jest-message-util]` Add support for [error causes](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/cause)
 
 ### Fixes
 
diff --git a/packages/jest-message-util/src/__tests__/messages.test.ts b/packages/jest-message-util/src/__tests__/messages.test.ts
@@ -413,3 +413,20 @@ it('getTopFrame should return a path for mjs files', () => {
 
   expect(frame!.file).toBe(expectedFile);
 });
+
+it('should return the error cause if there is one', () => {
+  const error = new Error('Test exception');
+  // We need to do it this way because in oder Javascript engines the constructor does not allow supplying a cause.
+  error.cause = new Error('Cause Error');
+  const message = formatExecError(
+    error,
+    {
+      rootDir: '',
+      testMatch: [],
+    },
+    {
+      noStackTrace: false,
+    },
+  );
+  expect(message).toEqual(expect.stringContaining('Cause'));
+});
diff --git a/packages/jest-message-util/src/index.ts b/packages/jest-message-util/src/index.ts
@@ -122,18 +122,20 @@ function warnAboutWrongTestEnvironment(error: string, env: 'jsdom' | 'node') {
 // `before/after each` hooks). If it's thrown, none of the tests in the file
 // are executed.
 export const formatExecError = (
-  error: Error | TestResult.SerializableError | string | undefined,
+  error: Error | TestResult.SerializableError | string | undefined | number,
   config: StackTraceConfig,
   options: StackTraceOptions,
   testPath?: string,
   reuseMessage?: boolean,
+  noTitle?: boolean,
 ): string => {
   if (!error || typeof error === 'number') {
     error = new Error(`Expected an Error, but "${String(error)}" was thrown`);
     error.stack = '';
   }
 
   let message, stack;
+  let cause = '';
 
   if (typeof error === 'string' || !error) {
     error || (error = 'EMPTY ERROR');
@@ -145,6 +147,27 @@ export const formatExecError = (
       typeof error.stack === 'string'
         ? error.stack
         : `thrown: ${prettyFormat(error, {maxDepth: 3})}`;
+    if ('cause' in error) {
+      const prefix = '\n\nCause:\n';
+      if (typeof error.cause === 'string') {
+        cause += `${prefix}${error.cause}`;
+      } else if (typeof error.cause === 'number') {
+        cause += `${prefix}${error.cause.toString()}`;
+      } else if (error.cause instanceof Error) {
+        const formatted = formatExecError(
+          error.cause,
+          config,
+          options,
+          testPath,
+          reuseMessage,
+          true,
+        );
+        cause += `${prefix}${formatted}`;
+      }
+    }
+  }
+  if (cause !== '') {
+    cause = indentAllLines(cause);
   }
 
   const separated = separateMessageFromStack(stack || '');
@@ -174,13 +197,14 @@ export const formatExecError = (
 
   let messageToUse;
 
-  if (reuseMessage) {
+  if (reuseMessage || noTitle) {
     messageToUse = ` ${message.trim()}`;
   } else {
     messageToUse = `${EXEC_ERROR_MESSAGE}\n\n${message}`;
   }
+  const title = noTitle ? '' : `${TITLE_INDENT + TITLE_BULLET}`;
 
-  return `${TITLE_INDENT + TITLE_BULLET + messageToUse + stack}\n`;
+  return `${title + messageToUse + stack + cause}\n`;
 };
 
 const removeInternalStackEntries = (
