@wordpress/compose
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@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.
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);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 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 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.
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 inspired by flowRight from Lodash and works the same way. 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 ) )
);
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 such language features and APIs, you should include the polyfill shipped in @wordpress/babel-preset-default in your code.
For more details, you can refer to each Higher Order Component's README file. Available components are located here.
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.
This is inspired by lodash's flowRight function.
Related
Given a function mapping a component to an enhanced component and modifier name, returns the enhanced component augmented with a generated displayName.
Parameters
( Inner: TInner ) => TOuter: Function mapping component to enhanced component.string: Seed name from which to generated display name.Returns
A simplified and properly typed version of lodash's debounce, that always uses timers instead of sometimes using rAF.
Creates a debounced function that delays invoking func until after wait milliseconds have elapsed since the last time the debounced function was invoked. The debounced function comes with a cancel method to cancel delayed func invocations and a flush method to immediately invoke them. Provide options to indicate whether func should be invoked on the leading and/or trailing edge of the wait timeout. The func is invoked with the last arguments provided to the debounced function. Subsequent calls to the debounced function return the result of the last func invocation.
Note: If leading and trailing options are true, func is invoked on the trailing edge of the timeout only if the debounced function is invoked more than once during the wait timeout.
If wait is 0 and leading is false, func invocation is deferred until the next tick, similar to setTimeout with a timeout of 0.
Parameters
Function: The function to debounce.number: The number of milliseconds to delay.Partial< DebounceOptions >: The options object.boolean: Specify invoking on the leading edge of the timeout.number: The maximum time func is allowed to be delayed before it's invoked.boolean: Specify invoking on the trailing edge of the timeout.Returns
Higher-order component creator, creating a new component which renders if the given condition is satisfied or with the given optional prop name.
Usage
type Props = { foo: string };
const Component = ( props: Props ) => <div>{ props.foo }</div>;
const ConditionalComponent = ifCondition( ( props: Props ) => props.foo.length !== 0 )( Component );
<ConditionalComponent foo="" />; // => null
<ConditionalComponent foo="bar" />; // => <div>bar</div>;
Parameters
( props: Props ) => boolean: Function to test condition.Returns
A constructor (factory) for ObservableMap, a map-like key/value data structure where the individual entries are observable: using the subscribe method, you can subscribe to updates for a particular keys. Each subscriber always observes one specific key and is not notified about any unrelated changes (for different keys) in the ObservableMap.
Returns
ObservableMap< K, V >: A new instance of the ObservableMap type.Composes multiple higher-order components into a single higher-order component. Performs left-to-right function composition, where each successive invocation is supplied the return value of the previous.
This is inspired by lodash's flow function.
Related
Deprecated Use
memoorPureComponentinstead.
Given a component returns the enhanced component augmented with a component only re-rendering when its props/state change
A simplified and properly typed version of lodash's throttle, that always uses timers instead of sometimes using rAF.
Creates a throttled function that only invokes func at most once per every wait milliseconds. The throttled function comes with a cancel method to cancel delayed func invocations and a flush method to immediately invoke them. Provide options to indicate whether func should be invoked on the leading and/or trailing edge of the wait timeout. The func is invoked with the last arguments provided to the throttled function. Subsequent calls to the throttled function return the result of the last func invocation.
Note: If leading and trailing options are true, func is invoked on the trailing edge of the timeout only if the throttled function is invoked more than once during the wait timeout.
If wait is 0 and leading is false, func invocation is deferred until the next tick, similar to setTimeout with a timeout of 0.
Parameters
Function: The function to throttle.number: The number of milliseconds to throttle invocations to.Partial< ThrottleOptions >: The options object.boolean: Specify invoking on the leading edge of the timeout.boolean: Specify invoking on the trailing edge of the timeout.Returns
React hook returns an array which items get asynchronously appended from a source array. This behavior is useful if we want to render a list of items asynchronously for performance reasons.
Parameters
T[]: Source array.AsyncListConfig: Configuration object.Returns
T[]: Async array.In Dialogs/modals, the tabbing must be constrained to the content of the wrapper element. This hook adds the behavior to the returned ref.
Usage
import { useConstrainedTabbing } from '@wordpress/compose';
const ConstrainedTabbingExample = () => {
const constrainedTabbingRef = useConstrainedTabbing();
return (
<div ref={ constrainedTabbingRef }>
<Button />
<Button />
</div>
);
};
Returns
import('react').RefCallback<Element>: Element Ref.Deprecated
Copies the text to the clipboard when the element is clicked.
Parameters
import('react').RefObject<string | Element | NodeListOf<Element>>: Reference with the element.string|Function: The text to copy.[number]: Optional timeout to reset the returned state. 4 seconds by default.Returns
boolean: Whether or not the text has been copied. Resets after the timeout.Copies the given text to the clipboard when the element is clicked.
Parameters
string | (() => string): The text to copy. Use a function if not already available and expensive to compute.Function: Called when to text is copied.Returns
import('react').Ref<TElementType>: A ref to assign to the target element.Debounces a function similar to Lodash's debounce. A new debounced function will be returned and any scheduled calls cancelled if any of the arguments change, including the function to debounce, so please wrap functions created on render in components in useCallback.
Related
Parameters
TFunc: The function to debounce.[number]: The number of milliseconds to delay.[import('../../utils/debounce').DebounceOptions]: The options object.Returns
import('../../utils/debounce').DebouncedFunc<TFunc>: Debounced function.Helper hook for input fields that need to debounce the value before using it.
Parameters
any: The default value to use.Returns
[string, Function, string]: The input value, the setter and the debounced input value.In some circumstances, such as block previews, all focusable DOM elements (input fields, links, buttons, etc.) need to be disabled. This hook adds the behavior to disable nested DOM elements to the returned ref.
If you can, prefer the use of the inert HTML attribute.
Usage
import { useDisabled } from '@wordpress/compose';
const DisabledExample = () => {
const disabledRef = useDisabled();
return (
<div ref={ disabledRef }>
<a href="#">This link will have tabindex set to -1</a>
<input
placeholder="This input will have the disabled attribute added to it."
type="text"
/>
</div>
);
};
Parameters
Object: Configuration object.boolean=: Whether the element should be disabled.Returns
import('react').RefCallback<HTMLElement>: Element Ref.Dispatches a bubbling focus event when the iframe receives focus. Use onFocus as usual on the iframe or a parent element.
Returns
RefCallback< HTMLIFrameElement >: Ref to pass to the iframe.Hook used to focus the first tabbable element on mount.
Usage
import { useFocusOnMount } from '@wordpress/compose';
const WithFocusOnMount = () => {
const ref = useFocusOnMount();
return (
<div ref={ ref }>
<Button />
<Button />
</div>
);
};
Parameters
boolean | 'firstElement': Focus on mount mode.Returns
import('react').RefCallback<HTMLElement>: Ref callback.Adds the unmount behavior of returning focus to the element which had it previously as is expected for roles like menus or dialogs.
Usage
import { useFocusReturn } from '@wordpress/compose';
const WithFocusReturn = () => {
const ref = useFocusReturn();
return (
<div ref={ ref }>
<Button />
<Button />
</div>
);
};
Parameters
[() => void]: Overrides the default return behavior.Returns
import('react').RefCallback<HTMLElement>: Element Ref.Provides a unique instance ID.
Parameters
object: Object reference to create an id for.[string]: Prefix for the unique id.[string | number]: Default ID to use.Returns
string | number: The unique instance id.Preferred over direct usage of useLayoutEffect when supporting server rendered components (SSR) because currently React throws a warning when using useLayoutEffect in that environment.
Attach a keyboard shortcut handler.
Related
callback parameter.Parameters
string[]|string: Keyboard Shortcuts.(e: import('mousetrap').ExtendedKeyboardEvent, combo: string) => void: Shortcut callback.WPKeyboardShortcutConfig: Shortcut options.Runs a media query and returns its value when it changes.
Parameters
[string]: Media Query.Returns
boolean: return value of the media query.Merges refs into one ref callback.
It also ensures that the merged ref callbacks are only called when they change (as a result of a useCallback dependency update) OR when the ref value changes, just as React does when passing a single ref callback to the component.
As expected, if you pass a new function on every render, the ref callback will be called after every render.
If you don't wish a ref callback to be called after every render, wrap it with useCallback( callback, dependencies ). When a dependency changes, the old ref callback will be called with null and the new ref callback will be called with the same value.
To make ref callbacks easier to use, you can also pass the result of useRefEffect, which makes cleanup easier by allowing you to return a cleanup function instead of handling null.
It's also possible to disable a ref (and its behaviour) by simply not passing the ref.
const ref = useRefEffect( ( node ) => {
node.addEventListener( ... );
return () => {
node.removeEventListener( ... );
};
}, [ ...dependencies ] );
const otherRef = useRef();
const mergedRefs useMergeRefs( [
enabled && ref,
otherRef,
] );
return <div ref={ mergedRefs } />;
Parameters
Array<TRef>: The refs to be merged.Returns
import('react').RefCallback<TypeFromRef<TRef>>: The merged ref callback.React hook that lets you observe an entry in an ObservableMap. The hook returns the current value corresponding to the key, or undefined when there is no value stored. It also observes changes to the value and triggers an update of the calling component in case the value changes.
Parameters
ObservableMap< K, V >: The ObservableMap to observe.K: The map key to observe.Returns
V | undefined: The value corresponding to the map key requested.Use something's value from the previous render. Based on https://usehooks.com/usePrevious/.
Parameters
T: The value to track.Returns
T | undefined: The value from the previous render.Hook returning whether the user has a preference for reduced motion.
Returns
boolean: Reduced motion preference value.Effect-like ref callback. Just like with useEffect, this allows you to return a cleanup function to be run if the ref changes or one of the dependencies changes. The ref is provided as an argument to the callback functions. The main difference between this and useEffect is that the useEffect callback is not called when the ref changes, but this is. Pass the returned ref callback as the component's ref and merge multiple refs with useMergeRefs.
It's worth noting that if the dependencies array is empty, there's not strictly a need to clean up event handlers for example, because the node is to be removed. It is necessary if you add dependencies because the ref callback will be called multiple times for the same node.
Parameters
( node: TElement ) => ( () => void ) | void: Callback with ref as argument.DependencyList: Dependencies of the callback.Returns
RefCallback< TElement | null >: Ref callback.Hook which allows to listen the resize event of any target element when it changes sizes. _Note: useResizeObserver will report null until after first render.
Usage
const App = () => {
const [ resizeListener, sizes ] = useResizeObserver();
return (
<div>
{ resizeListener }
Your content here
</div>
);
};
useState with undo/redo history.
Parameters
T: Initial value.Returns
Throttles a function similar to Lodash's throttle. A new throttled function will be returned and any scheduled calls cancelled if any of the arguments change, including the function to throttle, so please wrap functions created on render in components in useCallback.
Related
Parameters
TFunc: The function to throttle.[number]: The number of milliseconds to throttle invocations to.[import('../../utils/throttle').ThrottleOptions]: The options object. See linked documentation for details.Returns
import('../../utils/debounce').DebouncedFunc<TFunc>: Throttled function.Returns true if the viewport matches the given query, or false otherwise.
Usage
useViewportMatch( 'huge', '<' );
useViewportMatch( 'medium' );
Parameters
WPBreakpoint: Breakpoint size name.[WPViewportOperator]: Viewport operator.Returns
boolean: Whether viewport matches query.Hook that performs a shallow comparison between the preview value of an object and the new one, if there's a difference, it prints it to the console. this is useful in performance related work, to check why a component re-renders.
Usage
function MyComponent( props ) {
useWarnOnChange( props );
return 'Something';
}
Parameters
object: Object which changes to compare.string: Just a prefix to show when console logging.Deprecated
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
Record<keyof GlobalEventHandlersEventMap, 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
any: Higher-order component.A Higher Order Component used to be provide a unique instance ID by component.
A higher-order component used to provide and manage delayed function calls that ought to be bound to a component's lifecycle.
Deprecated Use
useStateinstead.
A Higher Order Component used to provide and manage internal component state via props.
Parameters
any: Optional initial state of the component.Returns
any: A higher order component wrapper accepting a component that takes the state props + its own props + setState and returning a component that only accepts the own props.This is an individual package that's part of the Gutenberg project. The project is organized as a monorepo. It's made up of multiple self-contained software packages, each with a specific purpose. The packages in this monorepo are published to npm and used by WordPress as well as other software projects.
To find out more about contributing to this package or Gutenberg as a whole, please read the project's main contributor guide.
FAQs
WordPress higher-order components (HOCs).
We found that @wordpress/compose demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 23 open source maintainers collaborating on the project.
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