jasmine/src/core/ExpectationResult.js

//TODO: expectation result may make more sense as a presentation of an expectation.
getJasmineRequireObj().buildExpectationResult = function() {
  function buildExpectationResult(options) {
    var messageFormatter = options.messageFormatter || function() {},
      stackFormatter = options.stackFormatter || function() {};

    var result = {
      matcherName: options.matcherName,
      message: message(),
      stack: stack(),
      passed: options.passed
    };

    if(!result.passed) {
      result.expected = options.expected;
      result.actual = options.actual;
    }

    return result;

    function message() {
      if (options.passed) {
        return 'Passed.';
      } else if (options.message) {
        return options.message;
      } else if (options.error) {
        return messageFormatter(options.error);
      }
      return '';
    }

    function stack() {
      if (options.passed) {
        return '';
      }

      var error = options.error;
      if (!error) {
        try {
          throw new Error(message());
        } catch (e) {
          error = e;
        }
      }
      return stackFormatter(error);
    }
  }

  return buildExpectationResult;
};