Enzyme Context Utils

The module exports some utilities that improve the ease of authoring enzyme-context plugins:

ContextWatcher()

A class that gets the context of a Provider and notifies listeners when the context changes.

Arguments

1. render ((WatcherComponent: React.ComponentClass) => React.ReactElement): a function that accepts a react component as its only argument and must return some JSX that renders that react component as a child of a Provider.
2. childContextTypes (ValidationMap ([optional])): the childContextTypes of the provider. This argument only needs to be passed if the root component returned by render does not define childContextTypes.

Attributes

• value (any): the context of the provider

Methods

• listen(listener: (context: any) => void): registers a listener to be notified of context changes

  • Arguments
    1. listener: ((context: any) => void): the listener function that will be called with the context whenever it changes

• stop(): stops listening for changes and cleans up any mounted components

Example

import { createStore } from 'redux';
import { Provider } from 'react-redux';
import { getContextFromProvider } from 'enzyme-context-utils';

const store = createStore(() => ({}));
const context = new ContextWatcher(Watcher => (
  <Provider store={store}>
    <Watcher />
  </Provider>
));

expect(context.value).toEqual({ store });
context.listen(newContext => {
  // called whenever context changes
});

bindContextToWrapper(context: ContextWatcher) => (wrapper: ReactWrapper | ShallowWrapper) => () => void;

A utility that binds a ContextWatcher to a given enzyme wrapper, updating its context whenever the watcher's context changes.

Arguments

1. context (ContextWatcher): the context to watch

Returns

• (wrapper: ReactWrapper | ShallowWrapper) => () => void: a function that accepts the enzyme wrapper to bind to
  • Arguments
    1. wrapper (ReactWrapper | ShallowWrapper): the enzyme wrapper to bind to
  • Returns: () => void: a function that will stop listening for context changes when called

Example

This method is useful for setting the updater attributes of an enzyme-context plugin return:

const myPlugin = (node, options) => {
  const store = createStore(() => ({}));
  const context = new ContextWatcher(Watcher => (
    <Provider store={store}>
      <Watcher />
    </Provider>
  ));

  return {
    node,
    options,
    controller: store,
    updater: bindContextToWrapper(context),
  };
};

EnzymePlugin<O extends object, C>

A TypeScript interface defining an enzyme-context plugin.

Arguments

1. O (extends object): the shape of the custom parameters users may pass to mount/shallow when this plugin is enabled.
2. C: the type of the controller that will be returned.

Example

import { EnzymePlugin } from 'enzyme-context-utils';
import { createStore, Store, AnyAction } from 'redux';

interface ReduxPluginMountOptions {
  initialActions?: AnyAction[];
}

const reduxPlugin: EnzymePlugin<ReduxPluginMountOptions, Store> = (node, options) => {
  const store = createStore(() => ({}));

  return {
    node,
    options: {
      ...options,
      context: {
        ...options.context,
        store,
      },
    },
    controller: store,
  };
};