From ba37ffda9e55832be42f340d865f974be98625bb Mon Sep 17 00:00:00 2001
From: Mitchell Austin <mr.fye@oneandthesame.net>
Date: Sun, 10 Oct 2021 17:36:51 -0700
Subject: [PATCH] Hide horizontal overflow in `Navigator` (#35332)

* Hide horizontal overflow in `Navigator`

* Let `NavigatorScreen` show/scroll horizontal overflow

* Fix missing classname in reduced motion context, and memoise
classname.

* Memoise classname and comment

* Added dialog to storybook

* Add a screen with horizontal overflow to Navigator story

* Edit style prop to silence console

* Cosmetic touch-ups for Navigator story

Co-authored-by: Marco Ciampini <marco.ciampo@gmail.com>
---
 .../navigator-provider/component.tsx          | 23 +++--
 .../navigator/navigator-screen/component.tsx  | 16 +++-
 .../components/src/navigator/stories/index.js | 87 +++++++++++++++----
 3 files changed, 100 insertions(+), 26 deletions(-)

diff --git a/packages/components/src/navigator/navigator-provider/component.tsx b/packages/components/src/navigator/navigator-provider/component.tsx
index 5f8e82e6137213..df17ba55b05591 100644
--- a/packages/components/src/navigator/navigator-provider/component.tsx
+++ b/packages/components/src/navigator/navigator-provider/component.tsx
@@ -3,11 +3,12 @@
  */
 // eslint-disable-next-line no-restricted-imports
 import type { Ref } from 'react';
+import { css } from '@emotion/react';
 
 /**
  * WordPress dependencies
  */
-import { useState } from '@wordpress/element';
+import { useMemo, useState } from '@wordpress/element';
 
 /**
  * Internal dependencies
@@ -17,6 +18,7 @@ import {
 	useContextSystem,
 	WordPressComponentProps,
 } from '../../ui/context';
+import { useCx } from '../../utils/hooks/use-cx';
 import { View } from '../../view';
 import { NavigatorContext } from '../context';
 import type { NavigatorProviderProps, NavigatorPath } from '../types';
@@ -25,17 +27,26 @@ function NavigatorProvider(
 	props: WordPressComponentProps< NavigatorProviderProps, 'div' >,
 	forwardedRef: Ref< any >
 ) {
-	const { initialPath, children, ...otherProps } = useContextSystem(
-		props,
-		'NavigatorProvider'
-	);
+	const {
+		initialPath,
+		children,
+		className,
+		...otherProps
+	} = useContextSystem( props, 'NavigatorProvider' );
 
 	const [ path, setPath ] = useState< NavigatorPath >( {
 		path: initialPath,
 	} );
 
+	const cx = useCx();
+	const classes = useMemo(
+		// Prevents horizontal overflow while animating screen transitions
+		() => cx( css( { overflowX: 'hidden' } ), className ),
+		[ className ]
+	);
+
 	return (
-		<View ref={ forwardedRef } { ...otherProps }>
+		<View ref={ forwardedRef } className={ classes } { ...otherProps }>
 			<NavigatorContext.Provider value={ [ path, setPath ] }>
 				{ children }
 			</NavigatorContext.Provider>
diff --git a/packages/components/src/navigator/navigator-screen/component.tsx b/packages/components/src/navigator/navigator-screen/component.tsx
index 95d7fec931dbbe..178fa71965a357 100644
--- a/packages/components/src/navigator/navigator-screen/component.tsx
+++ b/packages/components/src/navigator/navigator-screen/component.tsx
@@ -5,11 +5,12 @@
 import type { Ref } from 'react';
 // eslint-disable-next-line no-restricted-imports
 import { motion, MotionProps } from 'framer-motion';
+import { css } from '@emotion/react';
 
 /**
  * WordPress dependencies
  */
-import { useContext, useEffect, useState } from '@wordpress/element';
+import { useContext, useEffect, useState, useMemo } from '@wordpress/element';
 import { useReducedMotion, useFocusOnMount } from '@wordpress/compose';
 import { isRTL } from '@wordpress/i18n';
 
@@ -21,6 +22,7 @@ import {
 	useContextSystem,
 	WordPressComponentProps,
 } from '../../ui/context';
+import { useCx } from '../../utils/hooks/use-cx';
 import { View } from '../../view';
 import { NavigatorContext } from '../context';
 import type { NavigatorScreenProps } from '../types';
@@ -38,7 +40,7 @@ type Props = Omit<
 >;
 
 function NavigatorScreen( props: Props, forwardedRef: Ref< any > ) {
-	const { children, path, ...otherProps } = useContextSystem(
+	const { children, className, path, ...otherProps } = useContextSystem(
 		props,
 		'NavigatorScreen'
 	);
@@ -48,6 +50,13 @@ function NavigatorScreen( props: Props, forwardedRef: Ref< any > ) {
 	const isMatch = currentPath.path === path;
 	const ref = useFocusOnMount();
 
+	const cx = useCx();
+	const classes = useMemo(
+		// Ensures horizontal overflow is visually accessible
+		() => cx( css( { overflowX: 'auto' } ), className ),
+		[ className ]
+	);
+
 	// This flag is used to only apply the focus on mount when the actual path changes.
 	// It avoids the focus to happen on the first render.
 	const [ hasPathChanged, setHasPathChanged ] = useState( false );
@@ -61,7 +70,7 @@ function NavigatorScreen( props: Props, forwardedRef: Ref< any > ) {
 
 	if ( prefersReducedMotion ) {
 		return (
-			<View ref={ forwardedRef } { ...otherProps }>
+			<View ref={ forwardedRef } className={ classes } { ...otherProps }>
 				{ children }
 			</View>
 		);
@@ -107,6 +116,7 @@ function NavigatorScreen( props: Props, forwardedRef: Ref< any > ) {
 	return (
 		<motion.div
 			ref={ hasPathChanged ? ref : undefined }
+			className={ classes }
 			{ ...otherProps }
 			{ ...animatedProps }
 		>
diff --git a/packages/components/src/navigator/stories/index.js b/packages/components/src/navigator/stories/index.js
index 42a5a639e6e671..172c0f5f6f6b91 100644
--- a/packages/components/src/navigator/stories/index.js
+++ b/packages/components/src/navigator/stories/index.js
@@ -2,6 +2,9 @@
  * Internal dependencies
  */
 import Button from '../../button';
+import { Card, CardBody, CardHeader } from '../../card';
+import { HStack } from '../../h-stack';
+import { Flyout } from '../../flyout';
 import { NavigatorProvider, NavigatorScreen, useNavigator } from '../';
 
 export default {
@@ -19,23 +22,73 @@ function NavigatorButton( { path, isBack = false, ...props } ) {
 	);
 }
 
-const MyNavigation = () => (
-	<NavigatorProvider initialPath="/">
-		<NavigatorScreen path="/">
-			<p>This is the home screen.</p>
-			<NavigatorButton isPrimary path="/child">
-				Navigate to child screen.
-			</NavigatorButton>
-		</NavigatorScreen>
-
-		<NavigatorScreen path="/child">
-			<p>This is the child screen.</p>
-			<NavigatorButton isPrimary path="/" isBack>
-				Go back
-			</NavigatorButton>
-		</NavigatorScreen>
-	</NavigatorProvider>
-);
+const MyNavigation = () => {
+	return (
+		<NavigatorProvider initialPath="/">
+			<NavigatorScreen path="/">
+				<Card>
+					<CardBody>
+						<p>This is the home screen.</p>
+
+						<HStack justify="flex-start" wrap>
+							<NavigatorButton isPrimary path="/child">
+								Navigate to child screen.
+							</NavigatorButton>
+
+							<NavigatorButton path="/overflow-child">
+								Navigate to screen with horizontal overflow.
+							</NavigatorButton>
+
+							<Flyout
+								trigger={ <Button>Open test dialog</Button> }
+								placement="bottom-start"
+							>
+								<CardHeader>Go</CardHeader>
+								<CardBody>Stuff</CardBody>
+							</Flyout>
+						</HStack>
+					</CardBody>
+				</Card>
+			</NavigatorScreen>
+
+			<NavigatorScreen path="/child">
+				<Card>
+					<CardBody>
+						<p>This is the child screen.</p>
+						<NavigatorButton isPrimary path="/" isBack>
+							Go back
+						</NavigatorButton>
+					</CardBody>
+				</Card>
+			</NavigatorScreen>
+			<NavigatorScreen path="/overflow-child">
+				<Card>
+					<CardBody>
+						<NavigatorButton isPrimary path="/" isBack>
+							Go back
+						</NavigatorButton>
+						<div
+							style={ {
+								display: 'inline-block',
+								background: 'papayawhip',
+							} }
+						>
+							<span
+								style={ {
+									color: 'palevioletred',
+									whiteSpace: 'nowrap',
+									fontSize: '42vw',
+								} }
+							>
+								¯\_(ツ)_/¯
+							</span>
+						</div>
+					</CardBody>
+				</Card>
+			</NavigatorScreen>
+		</NavigatorProvider>
+	);
+};
 
 export const _default = () => {
 	return <MyNavigation />;