Function separateMessageFromStack

packages/jest-message-util/src/index.ts:517–538

(
  content: string,
)

// Error object, so we have to regexp out the message from the stack string
// to format it.
export const separateMessageFromStack = (
  content: string,
): {message: string; stack: string} => {
  if (!content) {
    return {message: '', stack: ''};
  }

  // All lines up to what looks like a stack -- or if nothing looks like a stack
  // (maybe it's a code frame instead), just the first non-empty line.
  // If the error is a plain "Error:" instead of a SyntaxError or TypeError we
  // remove the prefix from the message because it is generally not useful.
  const messageMatch = content.match(
    /^(?:Error: )?([\S\s]*?(?=\n\s*at\s.*:\d*:\d*)|\s*.*)([\S\s]*)$/,
  );
  if (!messageMatch) {
    // For typescript
    throw new Error('If you hit this error, the regex above is buggy.');
  }
  const message = removeBlankErrorLine(messageMatch[1]);
  const stack = removeBlankErrorLine(messageMatch[2]);
  return {message, stack};
};