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

[ibuibu]

Summary

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

Closes #12053

Test plan

Test code

// sample.js

const testFunc = () => {
  const a = new Error("a");
  const b = new Error("b", { cause: a });
  const c = new Error("c", { cause: b });
  throw c;
};

module.exports = testFunc;

// sample.test.js

const testFunc = require("./sample");

const a = new Error("a");
const b = new Error("b", { cause: a });
const c = new Error("c", { cause: b });

test("pass: new Error", () => {
  expect(testFunc).toThrow(c);
});

test("pass: object", () => {
  expect(testFunc).toThrow({ message: "c", cause: b });
});

test("fail: new Error", () => {
  expect(testFunc).toThrow(b);
});

Result

[SimenB]

Thanks, looks good!

[SimenB]

Do not put these helpers inside the matcher - move them to the module level

[SimenB]

Instead of the entire 2022, just pull in what's needed for Error.prototype.cause

[SimenB]

same here, only pull in the error one from 2022

[ibuibu]

I tried some patterns.

    "lib": ["es2020","es2022.error", "dom"],

    "lib": ["es2022.error", "es2020", "dom"],

    "lib": ["es2022.error", "dom"],

However, the following errors occured in compilation.
https://github.com/facebook/jest/actions/runs/3470037100/jobs/5797753863

Error: node_modules/typescript/lib/lib.es2022.error.d.ts(69,8): error TS2304: Cannot find name 'AggregateError'.
Error: node_modules/typescript/lib/lib.es2022.error.d.ts(74,8): error TS2304: Cannot find name 'AggregateError'.

I investigated but could not find the cause.

[ibuibu]

I find the cause. AggregateError is defined in es2021.promise.

I could build by following config.

    "lib": ["es2020", "es2021.promise", "es2022.error", "dom"],

However, I cannot the reason why "es2020" and "dom" are set. I could build by following config too.

    "lib": ["es2021.promise", "es2022.error" ],

Can you tell me the reason why "es2020" and "dom" are needed?

[ibuibu]

I commied below because I was afraid of side effects.

    "lib": ["es2020", "es2021.promise", "es2022.error", "dom"],

[SimenB]

why are these 2 functions?

[ibuibu]

Currently, if { message: 'foo' } is given, the standard output is "Expected message: foo".

To maintain this current behavior, I separated the functions so that only error.message is returned in the first loop.

[SimenB]

_createMessageAndCause is only called from within itself or createMessageAndCause, can't they be combined?

[SimenB]

Can you add a snapshot test or something which shows what the error looks like if the cause is different? all the messageAndCause calls seems uncovered in the failing case

[ibuibu]

Can you add a snapshot test or something which shows what the error looks like if the cause is different? all the messageAndCause calls seems uncovered in the failing case

I understand that the reason for the snapshot test is to verify that the result string of jest's standard error output on fail is as expected. In particular, the "Expected (Received) message and cause" part.

However, In CI test, the same snap file is shared by v14 and v16, so the v14 test, which does not support error cause, always fails because it expects the existence of a cause.

Therefore, as an alternative, we tried the following, but none of them were possible.

• Put a decision to skip the test in case of v14.

  • CI test fails because snapshot is treated as obsolete in v14.(https://github.com/facebook/jest/actions/runs/3470613139/jobs/5799045755)

• Use toThrowErrorMatchingInlineSnapshot

  • Error: Couldn't infer stack frame for inline snapshot.

• toThrowError(new Error(expected(received).toThrowError(expected)) Expected message and cause: "{ message: good, cause: { message: B, cause: { message: A }}}" Received message and cause: "{ message: bad, cause: { message: B, cause: { message: A }}" at packages/expect/src/__tests__/toThrowMatchers.test.ts:315:21))

  • Since the output includes results with control characters using chalk in Receive, it is difficult to compare the results without using the formatReceived function or other functions defined in toThrowMatchers.ts.

Therefore, I gave up judging the exact match of strings and used Regexp to judge whether or not "Expected (Received) message and cause" is included, which we especially want to evaluate.

[SimenB]

can you add a changelog entry?

[SimenB]

can you use the helper? https://github.com/facebook/jest/blob/74776d8b581fabeb5c3993b6499643b8c6ffedf6/packages/test-utils/src/ConditionalTest.ts#L34

[SimenB]

_createMessageAndCause is only called from within itself or createMessageAndCause, can't they be combined?

[SimenB]

thanks!

[github-actions]

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