Is it possible to assert if a function is an empty function in jest?

I have a generic input component like this:

class GenericInputComponent extends React.Component {
   constructor (props) {
    super(props);

    this.handleChange = this.handleChange.bind(this);
  }

  handleChange (evt) {
    this.props.onChange(evt);
  }

  render () {
    return (<Something />)
  }
}

GenericComponent.defaultProps = {
  onChange: () => {}
}

For this component one of my tests is testing if component is using the default props:

it('should use default props', function () {
   delete props.onChange // Before this the onChange was jest.fn()

   rendered.unmount()

   rendered = shallow(<Input {...props} />)

   let onChange = () => {}

   expect(rendered.instance().props.onChange).toEqual(onChange)
   expect(rendered.instance().props.onChange).toBeInstanceOf(Function)  
})

The test fails on the following line:

expect(rendered.instance().props.onChange).toEqual(onChange)

and gives this error:

Expected value to equal:
      [Function onChange]
    Received:
      [Function onChange]

    Difference:

    Compared values have no visual difference.

From what I see it should be passing but it is not. Why? And is it possible to assert if the function that's being used is an empty function?

Moreover, if I try to spy on the function like this:

let onChangeSpy = jest.spyOn(rendered.instance().props, 'onChange')

I get this error:

`TypeError: Cannot assign to read only property 'onChange' of object '[object Object]'`

FYI, I am using shallow rendering for the test.

So is it possible to assert on an empty function? Also, this is the only thing keeping coverage from having a 100% coverage unfortunately.

This is expected because a function is an object, and objects are compared by references in JavaScript:

(() => {}) !== (() => {})

The method could be tested if it's empty by asserting onChange.toString(). But what should be tested here is that onChange is not just some empty function but a prop that was set by default. I.e. it should be:

expect(rendered.instance().props.onChange).toBe(GenericInputComponent.defaultProps.onChange)

The function can be optionally tested if it's empty:

expect(GenericInputComponent.defaultProps.onChange).toBeInstanceOf(Function);
expect(GenericInputComponent.defaultProps.onChange.toString().match(/\{(.*)}$/)[1])).toMatch(/^\s*$/);