Recursively dive() to deeply-wrapped components via Enzyme

diveTo.js

import merge from 'lodash/merge';

/**
 * Given an Enzyme ShallowWrapper and component identifier, dives() down until the
 * specified component is the root component.
 *
 * @param { Enzyme.ShallowWrapper } shallowWrapper - wrapper to dive into
 * @param { string } name of component to dive for (should match constructor name).
 * @param { object= } options to pass to dive()
 */
function diveTo(shallowWrapper, identifier, options = { context: {} }) {
  const element = shallowWrapper.getElement();
  if (!(element && element.type)) {
    throw new Error(`Failed to dive to ${identifier} - is it not in the component tree?`);
  }
  const instance = shallowWrapper.instance();
  if (instance && instance.constructor.name === identifier) {
    return shallowWrapper; // We found it!
  }

  // Enzyme limitation workaround: until https://github.com/airbnb/enzyme/issues/664 is resolved,
  // it's necessary to manually pass down child context like this
  const context = merge({}, instance && instance.getChildContext ? instance.getChildContext() : {},
    options.context);

  return diveTo(shallowWrapper.dive({ context }), identifier, { context });
}

usage.js

import { shallow } from 'enzyme';

const mountOptions = {};
const componentTree = /* Some JSX here, where <ComponentUnderTest> is deeply nested in HOCs... */;
const componentUnderTest = diveTo(shallow(componentTree, mountOptions), 'ComponentUnderTest', mountOptions);

Hi on this what does merge relate to as it doesn't specify

Hi on this what does merge relate to as it doesn't specify

Oops, sorry - I think it assumed "merge" had been imported from Lodash. I just switched example to Object.assign, but actually a deep merge is probably needed, so switching back but making it clearer.

But I'd check if any of this is still needed in latest Enzyme, it's possible it's now unecessary!