Refactor Dropdown to use functional component

packages/components/src/dropdown-menu/test/index.js

@@ -1,7 +1,7 @@
 /**
  * External dependencies
  */
-import { shallow, mount } from 'enzyme';
+import { fireEvent, render } from '@testing-library/react';
 
 /**
  * WordPress dependencies
@@ -13,7 +13,14 @@ import { arrowLeft, arrowRight, arrowUp, arrowDown } from '@wordpress/icons';
  * Internal dependencies
  */
 import DropdownMenu from '../';
-import { Button, MenuItem, NavigableMenu } from '../../';
+import { MenuItem } from '../../';
+
+function getMenuToggleButton( container ) {
+	return container.querySelector( '.components-dropdown-menu__toggle' );
+}
+function getNavigableMenu( container ) {
+	return container.querySelector( '.components-dropdown-menu__menu' );
+}
 
 describe( 'DropdownMenu', () => {
 	const children = ( { onClose } ) => <MenuItem onClick={ onClose } />;
@@ -46,55 +53,60 @@ describe( 'DropdownMenu', () => {
 
 	describe( 'basic rendering', () => {
 		it( 'should render a null element when neither controls nor children are assigned', () => {
-			const wrapper = shallow( <DropdownMenu /> );
+			const { container } = render( <DropdownMenu /> );
 
-			expect( wrapper.type() ).toBeNull();
+			expect( container.firstChild ).toBeNull();
 		} );
 
 		it( 'should render a null element when controls are empty and children is not specified', () => {
-			const wrapper = shallow( <DropdownMenu controls={ [] } /> );
+			const { container } = render( <DropdownMenu controls={ [] } /> );
 
-			expect( wrapper.type() ).toBeNull();
+			expect( container.firstChild ).toBeNull();
 		} );
 
 		it( 'should open menu on arrow down (controls)', () => {
-			const wrapper = mount( <DropdownMenu controls={ controls } /> );
-			const button = wrapper
-				.find( Button )
-				.filter( '.components-dropdown-menu__toggle' );
+			const {
+				container: { firstChild: dropdownMenuContainer },
+			} = render( <DropdownMenu controls={ controls } /> );
 
-			button.simulate( 'keydown', {
+			const button = getMenuToggleButton( dropdownMenuContainer );
+			button.focus();
+			fireEvent.keyDown( button, {
+				keyCode: DOWN,
 				stopPropagation: () => {},
 				preventDefault: () => {},
-				keyCode: DOWN,
 			} );
+			const menu = getNavigableMenu( dropdownMenuContainer );
+			expect( menu ).toBeTruthy();
 
-			expect( wrapper.find( NavigableMenu ) ).toHaveLength( 1 );
 			expect(
-				wrapper
-					.find( Button )
-					.filter( '.components-dropdown-menu__menu-item' )
+				dropdownMenuContainer.querySelectorAll(
+					'.components-dropdown-menu__menu-item'
+				)
 			).toHaveLength( controls.length );
 		} );
 
 		it( 'should open menu on arrow down (children)', () => {
-			const wrapper = mount( <DropdownMenu children={ children } /> );
-			const button = wrapper
-				.find( Button )
-				.filter( '.components-dropdown-menu__toggle' );
+			const {
+				container: { firstChild: dropdownMenuContainer },
+			} = render( <DropdownMenu children={ children } /> );
 
-			button.simulate( 'keydown', {
+			const button = getMenuToggleButton( dropdownMenuContainer );
+			button.focus();
+			fireEvent.keyDown( button, {
+				keyCode: DOWN,
 				stopPropagation: () => {},
 				preventDefault: () => {},
-				keyCode: DOWN,
 			} );
 
-			expect( wrapper.find( NavigableMenu ) ).toHaveLength( 1 );
+			expect( getNavigableMenu( dropdownMenuContainer ) ).toBeTruthy();
 
-			wrapper.find( MenuItem ).props().onClick();
-			wrapper.update();
+			const menuItem = dropdownMenuContainer.querySelector(
+				'.components-menu-item__button'
+			);
+			fireEvent.click( menuItem );
 
-			expect( wrapper.find( NavigableMenu ) ).toHaveLength( 0 );
+			expect( getNavigableMenu( dropdownMenuContainer ) ).toBeNull();
 		} );
 	} );
 } );

packages/components/src/dropdown/README.md

@@ -108,3 +108,18 @@ Use this o object to access properties/feature if the `Popover` component that a
 
  - Type: `Object`
  - Required: No
+
+### onClose
+
+A callback invoked when the popover should be closed.
+
+- Type: `Function`
+- Required: No
+
+### onToggle
+
+A callback invoked when the state of the popover changes from open to closed and vice versa.
+Function receives a boolean as a parameter. If `true`, the popover will open. If `false`, the popover will close.
+
+- Type: `Function`
+- Required: No

packages/components/src/dropdown/index.js

@@ -6,48 +6,53 @@ import classnames from 'classnames';
 /**
  * WordPress dependencies
  */
-import { Component, createRef } from '@wordpress/element';
+import { useRef, useEffect, useState } from '@wordpress/element';
 
 /**
  * Internal dependencies
  */
 import Popover from '../popover';
 
-class Dropdown extends Component {
-	constructor() {
-		super( ...arguments );
-
-		this.toggle = this.toggle.bind( this );
-		this.close = this.close.bind( this );
-		this.closeIfFocusOutside = this.closeIfFocusOutside.bind( this );
-
-		this.containerRef = createRef();
-
-		this.state = {
-			isOpen: false,
-		};
-	}
+function useObservableState( initialState, onStateChange ) {
+	const [ state, setState ] = useState( initialState );
+	return [
+		state,
+		( value ) => {
+			setState( value );
+			if ( onStateChange ) {
+				onStateChange( value );
+			}
+		},
+	];
+}
 
-	componentWillUnmount() {
-		const { isOpen } = this.state;
-		const { onToggle } = this.props;
-		if ( isOpen && onToggle ) {
-			onToggle( false );
-		}
-	}
+export default function Dropdown( {
+	renderContent,
+	renderToggle,
+	position = 'bottom right',
+	className,
+	contentClassName,
+	expandOnMobile,
+	headerTitle,
+	focusOnMount,
+	popoverProps,
+	onClose,
+	onToggle,
+} ) {
+	const containerRef = useRef();
+	const [ isOpen, setIsOpen ] = useObservableState( false, onToggle );
 
-	componentDidUpdate( prevProps, prevState ) {
-		const { isOpen } = this.state;
-		const { onToggle } = this.props;
-		if ( prevState.isOpen !== isOpen && onToggle ) {
-			onToggle( isOpen );
-		}
-	}
+	useEffect(
+		() => () => {
+			if ( onToggle ) {
+				onToggle( false );
+			}
+		},
+		[]
+	);
 
-	toggle() {
-		this.setState( ( state ) => ( {
-			isOpen: ! state.isOpen,
-		} ) );
+	function toggle() {
+		setIsOpen( ! isOpen );
 	}
 
 	/**
@@ -57,65 +62,48 @@ class Dropdown extends Component {
 	 * case the correct behavior is to keep the dropdown closed. The same applies
 	 * in case when focus is moved to the modal dialog.
 	 */
-	closeIfFocusOutside() {
+	function closeIfFocusOutside() {
 		if (
-			! this.containerRef.current.contains( document.activeElement ) &&
+			! containerRef.current.contains( document.activeElement ) &&
 			! document.activeElement.closest( '[role="dialog"]' )
 		) {
-			this.close();
+			close();
 		}
 	}
 
-	close() {
-		if ( this.props.onClose ) {
-			this.props.onClose();
+	function close() {
+		if ( onClose ) {
+			onClose();
 		}
-		this.setState( { isOpen: false } );
+		setIsOpen( false );
 	}
 
-	render() {
-		const { isOpen } = this.state;
-		const {
-			renderContent,
-			renderToggle,
-			position = 'bottom right',
-			className,
-			contentClassName,
-			expandOnMobile,
-			headerTitle,
-			focusOnMount,
-			popoverProps,
-		} = this.props;
+	const args = { isOpen, onToggle: toggle, onClose: close };
 
-		const args = { isOpen, onToggle: this.toggle, onClose: this.close };
-
-		return (
-			<div
-				className={ classnames( 'components-dropdown', className ) }
-				ref={ this.containerRef }
-			>
-				{ renderToggle( args ) }
-				{ isOpen && (
-					<Popover
-						position={ position }
-						onClose={ this.close }
-						onFocusOutside={ this.closeIfFocusOutside }
-						expandOnMobile={ expandOnMobile }
-						headerTitle={ headerTitle }
-						focusOnMount={ focusOnMount }
-						{ ...popoverProps }
-						className={ classnames(
-							'components-dropdown__content',
-							popoverProps ? popoverProps.className : undefined,
-							contentClassName
-						) }
-					>
-						{ renderContent( args ) }
-					</Popover>
-				) }
-			</div>
-		);
-	}
+	return (
+		<div
+			className={ classnames( 'components-dropdown', className ) }
+			ref={ containerRef }
+		>
+			{ renderToggle( args ) }
+			{ isOpen && (
+				<Popover
+					position={ position }
+					onClose={ close }
+					onFocusOutside={ closeIfFocusOutside }
+					expandOnMobile={ expandOnMobile }
+					headerTitle={ headerTitle }
+					focusOnMount={ focusOnMount }
+					{ ...popoverProps }
+					className={ classnames(
+						'components-dropdown__content',
+						popoverProps ? popoverProps.className : undefined,
+						contentClassName
+					) }
+				>
+					{ renderContent( args ) }
+				</Popover>
+			) }
+		</div>
+	);
 }
-
-export default Dropdown;