function throwingMatcher()

in packages/expect/src/index.ts [268:373]
78 lines of code
17 McCabe index (conditional complexity)

  function throwingMatcher(...args): any {
    let throws = true;
    const utils = {...matcherUtils, iterableEquality, subsetEquality};

    const matcherContext: MatcherState = {
      // When throws is disabled, the matcher will not throw errors during test
      // execution but instead add them to the global matcher state. If a
      // matcher throws, test execution is normally stopped immediately. The
      // snapshot matcher uses it because we want to log all snapshot
      // failures in a test.
      dontThrow: () => (throws = false),
      ...getState(),
      equals,
      error: err,
      isNot,
      promise,
      utils,
    };

    const processResult = (
      result: SyncExpectationResult,
      asyncError?: JestAssertionError,
    ) => {
      _validateResult(result);

      getState().assertionCalls++;

      if ((result.pass && isNot) || (!result.pass && !isNot)) {
        // XOR
        const message = getMessage(result.message);
        let error;

        if (err) {
          error = err;
          error.message = message;
        } else if (asyncError) {
          error = asyncError;
          error.message = message;
        } else {
          error = new JestAssertionError(message);

          // Try to remove this function from the stack trace frame.
          // Guard for some environments (browsers) that do not support this feature.
          if (Error.captureStackTrace) {
            Error.captureStackTrace(error, throwingMatcher);
          }
        }
        // Passing the result of the matcher with the error so that a custom
        // reporter could access the actual and expected objects of the result
        // for example in order to display a custom visual diff
        error.matcherResult = {...result, message};

        if (throws) {
          throw error;
        } else {
          getState().suppressedErrors.push(error);
        }
      }
    };

    const handleError = (error: Error) => {
      if (
        matcher[INTERNAL_MATCHER_FLAG] === true &&
        !(error instanceof JestAssertionError) &&
        error.name !== 'PrettyFormatPluginError' &&
        // Guard for some environments (browsers) that do not support this feature.
        Error.captureStackTrace
      ) {
        // Try to remove this and deeper functions from the stack trace frame.
        Error.captureStackTrace(error, throwingMatcher);
      }
      throw error;
    };

    let potentialResult: ExpectationResult;

    try {
      potentialResult =
        matcher[INTERNAL_MATCHER_FLAG] === true
          ? matcher.call(matcherContext, actual, ...args)
          : // It's a trap specifically for inline snapshot to capture this name
            // in the stack trace, so that it can correctly get the custom matcher
            // function call.
            (function __EXTERNAL_MATCHER_TRAP__() {
              return matcher.call(matcherContext, actual, ...args);
            })();

      if (isPromise(potentialResult)) {
        const asyncResult = potentialResult as AsyncExpectationResult;
        const asyncError = new JestAssertionError();
        if (Error.captureStackTrace) {
          Error.captureStackTrace(asyncError, throwingMatcher);
        }

        return asyncResult
          .then(aResult => processResult(aResult, asyncError))
          .catch(handleError);
      } else {
        const syncResult = potentialResult as SyncExpectationResult;

        return processResult(syncResult);
      }
    } catch (error: any) {
      return handleError(error);
    }
  };