@wordpress/compose

What is @wordpress/compose?

@wordpress/compose is a utility library for composing higher-order components (HOCs) in React. It provides a set of functions that help in managing component state, lifecycle, and other common patterns in a more declarative and functional way.

What are @wordpress/compose's main functionalities?

withState

The `withState` HOC is used to add state to a functional component. In this example, `count` is the state variable and `setCount` is the function to update it.

const { withState } = require('@wordpress/compose');
const MyComponent = ({ count, setCount }) => (
  <div>
    <p>{count}</p>
    <button onClick={() => setCount(count + 1)}>Increment</button>
  </div>
);
const EnhancedComponent = withState('count', 'setCount', 0)(MyComponent);

withInstanceId

The `withInstanceId` HOC provides a unique instance ID to each instance of the component. This can be useful for accessibility or for differentiating between multiple instances of the same component.

const { withInstanceId } = require('@wordpress/compose');
const MyComponent = ({ instanceId }) => (
  <div>
    <p>Instance ID: {instanceId}</p>
  </div>
);
const EnhancedComponent = withInstanceId(MyComponent);

compose

The `compose` function is used to combine multiple HOCs into a single HOC. In this example, `withState` and `withInstanceId` are combined to enhance `MyComponent`.

const { compose, withState, withInstanceId } = require('@wordpress/compose');
const MyComponent = ({ count, setCount, instanceId }) => (
  <div>
    <p>Instance ID: {instanceId}</p>
    <p>{count}</p>
    <button onClick={() => setCount(count + 1)}>Increment</button>
  </div>
);
const EnhancedComponent = compose(
  withState('count', 'setCount', 0),
  withInstanceId
)(MyComponent);

Other packages similar to @wordpress/compose

recompose

Recompose is a React utility belt for function components and higher-order components. It provides a similar set of utilities for managing state, lifecycle, and other common patterns in a more functional way. Compared to @wordpress/compose, Recompose offers a broader range of utilities and is more widely used in the React community.

redux

Redux is a state management library for JavaScript applications. While it is not specifically for composing higher-order components, it provides a way to manage application state in a predictable way. Compared to @wordpress/compose, Redux is more focused on global state management rather than enhancing individual components.

react-redux

React-Redux is the official React binding for Redux. It provides HOCs like `connect` to connect React components to the Redux store. Compared to @wordpress/compose, React-Redux is specifically designed for integrating Redux with React components.

README

Compose

The compose package is a collection of handy Hooks and Higher Order Components (HOCs) you can use to wrap your WordPress components and provide some basic features like: state, instance id, pure...

The compose function is an alias to flowRight from Lodash. It comes from functional programming, and allows you to compose any number of functions. You might also think of this as layering functions; compose will execute the last function first, then sequentially move back through the previous functions passing the result of each function upward.

An example that illustrates it for two functions:

const compose = ( f, g ) => x
    => f( g( x ) );

Here's a simplified example of compose in use from Gutenberg's PluginSidebar component:

Using compose:

const applyWithSelect = withSelect( ( select, ownProps ) => {
	return doSomething( select, ownProps);
} );
const applyWithDispatch = withDispatch( ( dispatch, ownProps ) => {
	return doSomethingElse( dispatch, ownProps );
} );

export default compose(
	withPluginContext,
	applyWithSelect,
	applyWithDispatch,
)( PluginSidebarMoreMenuItem );

Without compose, the code would look like this:

const applyWithSelect = withSelect( ( select, ownProps ) => {
	return doSomething( select, ownProps);
} );
const applyWithDispatch = withDispatch( ( dispatch, ownProps ) => {
	return doSomethingElse( dispatch, ownProps );
} );

export default withPluginContext(
	applyWithSelect(
		applyWithDispatch(
			PluginSidebarMoreMenuItem
		)
	)
);

Installation

Install the module

npm install @wordpress/compose --save

This package assumes that your code will run in an ES2015+ environment. If you're using an environment that has limited or no support for ES2015+ such as lower versions of IE then using core-js or @babel/polyfill will add support for these methods. Learn more about it in Babel docs.

API

For more details, you can refer to each Higher Order Component's README file. Available components are located here.

# compose

Composes multiple higher-order components into a single higher-order component. Performs right-to-left function composition, where each successive invocation is supplied the return value of the previous.

Parameters

• hocs ...Function: The HOC functions to invoke.

Returns

• Function: Returns the new composite function.

# createHigherOrderComponent

Given a function mapping a component to an enhanced component and modifier name, returns the enhanced component augmented with a generated displayName.

Parameters

• mapComponentToEnhancedComponent Function: Function mapping component to enhanced component.
• modifierName string: Seed name from which to generated display name.

Returns

• WPComponent: Component class with generated display name assigned.

# ifCondition

Higher-order component creator, creating a new component which renders if the given condition is satisfied or with the given optional prop name.

Parameters

• predicate Function: Function to test condition.

Returns

• Function: Higher-order component.

# pure

Given a component returns the enhanced component augmented with a component only rerendering when its props/state change

Parameters

• mapComponentToEnhancedComponent Function: Function mapping component to enhanced component.
• modifierName string: Seed name from which to generated display name.

Returns

• WPComponent: Component class with generated display name assigned.

# useMediaQuery

Runs a media query and returns its value when it changes.

Parameters

• query string: Media Query.

Returns

• boolean: return value of the media query.

# useReducedMotion

Hook returning whether the user has a preference for reduced motion.

Returns

• boolean: Reduced motion preference value.

# withGlobalEvents

Higher-order component creator which, given an object of DOM event types and values corresponding to a callback function name on the component, will create or update a window event handler to invoke the callback when an event occurs. On behalf of the consuming developer, the higher-order component manages unbinding when the component unmounts, and binding at most a single event handler for the entire application.

Parameters

• eventTypesToHandlers Object<string,string>: Object with keys of DOM event type, the value a name of the function on the original component's instance which handles the event.

Returns

• Function: Higher-order component.

# withInstanceId

A Higher Order Component used to be provide a unique instance ID by component.

Parameters

• WrappedComponent WPElement: The wrapped component.

Returns

• Component: Component with an instanceId prop.

# withSafeTimeout

A higher-order component used to provide and manage delayed function calls that ought to be bound to a component's lifecycle.

Parameters

• OriginalComponent Component: Component requiring setTimeout

Returns

• Component: Wrapped component.

# withState

A Higher Order Component used to provide and manage internal component state via props.

Parameters

• initialState ?Object: Optional initial state of the component.

Returns

• Component: Wrapped component.