Function assertionErrorMessage

packages/jest-jasmine2/src/assertionErrorMessage.ts:91–147

(
  error: AssertionErrorWithStack,
  options: DiffOptions,
)

};

function assertionErrorMessage(
  error: AssertionErrorWithStack,
  options: DiffOptions,
): string {
  const {expected, actual, generatedMessage, message, operator, stack} = error;
  const diffString = diff(expected, actual, options);
  const hasCustomMessage = !generatedMessage;
  const operatorName = getOperatorName(operator, stack);
  const trimmedStack = stack
    .replace(message, '')
    .replaceAll(/AssertionError(.*)/g, '');

  if (operatorName === 'doesNotThrow') {
    return `${
      buildHintString(assertThrowingMatcherHint(operatorName)) +
      chalk.reset('Expected the function not to throw an error.\n') +
      chalk.reset('Instead, it threw:\n')
    }  ${printReceived(actual)}${chalk.reset(
      hasCustomMessage ? `\n\nMessage:\n  ${message}` : '',
    )}${trimmedStack}`;
  }

  if (operatorName === 'throws') {
    if (error.generatedMessage) {
      return (
        buildHintString(assertThrowingMatcherHint(operatorName)) +
        chalk.reset(error.message) +
        chalk.reset(hasCustomMessage ? `\n\nMessage:\n  ${message}` : '') +
        trimmedStack
      );
    }
    return (
      buildHintString(assertThrowingMatcherHint(operatorName)) +
      chalk.reset('Expected the function to throw an error.\n') +
      chalk.reset("But it didn't throw anything.") +
      chalk.reset(hasCustomMessage ? `\n\nMessage:\n  ${message}` : '') +
      trimmedStack
    );
  }

  if (operatorName === 'fail') {
    return (
      buildHintString(assertMatcherHint(operator, operatorName, expected)) +
      chalk.reset(hasCustomMessage ? `Message:\n  ${message}` : '') +
      trimmedStack
    );
  }

  return `${
    buildHintString(assertMatcherHint(operator, operatorName, expected)) +
    chalk.reset(`Expected value ${operatorMessage(operator)}`)
  }  ${printExpected(expected)}\n${chalk.reset('Received:\n')}  ${printReceived(
    actual,
  )}${chalk.reset(hasCustomMessage ? `\n\nMessage:\n  ${message}` : '')}${
    diffString ? `\n\nDifference:\n\n${diffString}` : ''
  }${trimmedStack}`;
}