Jasmine matcher that checks the class of an object and some expected set of properties

gistfile1.js

toBeObjectWithProperties: function(expectedClass, expectedProperties) {
  var isObjectWithProperties = (this.actual instanceof expectedClass);
  for(var propertyName in expectedProperties){
    var expectedPropertyValue = expectedProperties[propertyName];
    isObjectWithProperties = isObjectWithProperties && (this.actual[propertyName] == expectedPropertyValue);
  }
  return isObjectWithProperties;
}