How does one access state on a nested React component wrapped by an HOC?

Question

I\'m using Enzyme, and we can actually use the example component given in the docs as a foundation for my question.

Let\'s assume this com

Answer 1

Thought it might be useful for you guys, as I stumbled upon this and have a fix.

In my case I have a component which is connected to redux.

class ComponentName extends Component {
...
}
export default connect(
  mapStateToProps,
  {
...
 }
)(ComponentName );

connect() is obviously a HOC component. So how do we access the "ComponentName" here?

Very simple:

component
    .find(ComponentName)
    .children()
    .first()
    .props() // returns ComponentName's props 

Answer 2

So it seems with the latest release of Enzyme there is a potential fix for this issue of accessing state on a child component.

Let's say we have <Foo> (note the use of React Router's <Link>)

class Foo extends Component {
  state = {
    bar: 'here is the state!'
  }

  render () {
    return (
      <Link to='/'>Here is a link</Link>
    )
  }
}

Note: The following code is only available in Enzyme v3.

Revisiting the test code, we are now able to write the following

it('puts the lotion in the basket', () => {
  const wrapper = mount(
    <MemoryRouter>
      <Foo />
    </MemoryRouter>
  )

  expect(wrapper.find(Foo).instance().state).toEqual({
    bar: 'here is the state!'
  })
})

Using wrapper.find(Child).instance() we are able to access Child's state even though it is a nested component. In previous Enzyme versions we could only access instance on the root. You can also call the setState function on the Child wrapper as well!

We can use a similar pattern with our shallowly rendered tests

it('puts the lotion in the basket shallowly', () => {
  const wrapper = shallow(
    <MemoryRouter>
      <Foo />
    </MemoryRouter>
  )

  expect(wrapper.find(Foo).dive().instance().state).toEqual({
    bar: 'here is the state!'
  })
})

Note the use of dive in the shallow test, which can be run on a single, non-DOM node, and will return the node, shallow-rendered.

---

Refs:

• https://github.com/airbnb/enzyme/issues/361
• https://github.com/airbnb/enzyme/issues/1289
• https://github.com/airbnb/enzyme/blob/master/docs/guides/migration-from-2-to-3