Today I Learned

A Hashrocket project

Spelunking Through Components With Enzyme's Dive

Most of the components we write have other components nested in them.

const Hello = ({ name }) => <h1>Hello {name}!</h1>;

const HelloContainer = (props) => (
  <div>
    <Hello {...props} />
  </div>
);

If we are to shallow render the above component using Enzyme, we’ll only see things one layer deep:

const wrapper = shallow(<HelloContainer name="World" />);
// wrapper ~= <div><Hello name="World" /></div>

If we’d like to explore a particular child of the rendered component further, we can do a little find and dive.

const wrapper = shallow(<HelloContainer name="World" />);
const helloWrapper = wrapper.find(Hello).dive();
expect(helloWrapper.text()).toEqual("Hello World!");

This allows us to make pinpoint assertions about how our components render without mounting the entire thing.

See a live example here.

h/t Vidal Ekechukwu