Update toThrow() to be able to use Error.cause

packages/expect/src/__tests__/toThrowMatchers.test.ts

@@ -278,6 +278,37 @@ describe.each(['toThrowError', 'toThrow'] as const)('%s', toThrow => {
     });
   });
 
+  describe('error message and cause', () => {
+    const errorA = new Error('A');
+    const errorB = new Error('B', {cause: errorA});
+    const expected = new Error('good', {cause: errorB});
+
+    describe('pass', () => {
+      test('isNot false', () => {
+        jestExpect(() => {
+          throw new Error('good', {cause: errorB});
+        })[toThrow](expected);
+      });
+
+      test('isNot true, incorrect message', () => {
+        jestExpect(() => {
+          throw new Error('bad', {cause: errorB});
+        }).not[toThrow](expected);
+      });
+
+      test('isNot true, incorrect cause', () => {
+        // less than v16 does not yet support Error.cause
+        if (Number(process.version.split('.')[0].slice(1)) < 16) {
+          expect(true).toBe(true);
+        } else {
+          jestExpect(() => {
+            throw new Error('good', {cause: errorA});
+          }).not[toThrow](expected);
+        }
+      });
+    });
+  });
+
   describe('asymmetric', () => {
     describe('any-Class', () => {
       describe('pass', () => {

packages/expect/src/__tests__/tsconfig.json

@@ -1,5 +1,8 @@
 {
   "extends": "../../../../tsconfig.test.json",
+  "compilerOptions": {
+    "lib": ["es2022"]
+  },
   "include": ["./**/*"],
   "references": [{"path": "../../"}]
 }

packages/expect/src/toThrowMatchers.ts

@@ -225,14 +225,48 @@ const toThrowExpectedObject = (
   thrown: Thrown | null,
   expected: Error,
 ): SyncExpectationResult => {
-  const pass = thrown !== null && thrown.message === expected.message;
+  function createMessageAndCause(error: Error): string {
+    if (error.cause instanceof Error) {
+      return _createMessageAndCause(error);
+    } else {
+      return error.message;
+    }
+  }
+
+  function _createMessageAndCause(error: Error): string {
+    if (error.cause instanceof Error) {
+      return `{ message: ${error.message}, cause: ${_createMessageAndCause(
+        error.cause,
+      )}}`;
+    } else {
+      return `{ message: ${error.message} }`;
+    }
+  }
+
+  function expectedMessageAndCause(error: Error) {
+    return error.cause === undefined
+      ? error.message
+      : createMessageAndCause(error);
+  }
+
+  function messageAndCause(error: Error) {
+    return error.cause === undefined ? 'message' : 'message and cause';
+  }
+
+  const pass =
+    thrown !== null &&
+    thrown.message === expected.message &&
+    createMessageAndCause(thrown.value) === createMessageAndCause(expected);
 
   const message = pass
     ? () =>
         // eslint-disable-next-line prefer-template
         matcherHint(matcherName, undefined, undefined, options) +
         '\n\n' +
-        formatExpected('Expected message: not ', expected.message) +
+        formatExpected(
+          `Expected ${messageAndCause(expected)}: not `,
+          expectedMessageAndCause(expected),
+        ) +
         (thrown !== null && thrown.hasMessage
           ? formatStack(thrown)
           : formatReceived('Received value:       ', thrown, 'value'))
@@ -242,22 +276,27 @@ const toThrowExpectedObject = (
         '\n\n' +
         (thrown === null
           ? // eslint-disable-next-line prefer-template
-            formatExpected('Expected message: ', expected.message) +
+            formatExpected(
+              `Expected ${messageAndCause(expected)}: `,
+              expectedMessageAndCause(expected),
+            ) +
             '\n' +
             DID_NOT_THROW
           : thrown.hasMessage
           ? // eslint-disable-next-line prefer-template
             printDiffOrStringify(
-              expected.message,
-              thrown.message,
-              'Expected message',
-              'Received message',
+              createMessageAndCause(expected),
+              createMessageAndCause(thrown.value),
+              `Expected ${messageAndCause(expected)}`,
+              `Received ${messageAndCause(thrown.value)}`,
               true,
             ) +
             '\n' +
             formatStack(thrown)
-          : formatExpected('Expected message: ', expected.message) +
-            formatReceived('Received value:   ', thrown, 'value'));
+          : formatExpected(
+              `Expected ${messageAndCause}: `,
+              expectedMessageAndCause,
+            ) + formatReceived('Received value:   ', thrown, 'value'));
 
   return {message, pass};
 };

packages/expect/tsconfig.json

@@ -1,7 +1,7 @@
 {
   "extends": "../../tsconfig.json",
   "compilerOptions": {
-    "lib": ["es2020", "dom"],
+    "lib": ["es2022", "dom"],
     "rootDir": "src",
     "outDir": "build"
   },