Focus trap and Modal Functionality (#145)

* Focus trap and Modal Functionality

* Changes

* Changes

* Update components/ui/Modal/Modal.tsx

Co-authored-by: Luis Alvarez D. <luis@vercel.com>

* changes

Co-authored-by: Luis Alvarez D. <luis@vercel.com>

components/cart/CartSidebarView/CartSidebarView.tsx

@@ -94,7 +94,7 @@ const CartSidebarView: FC = () => {
               My Cart
             </h2>
             <ul className="py-6 space-y-6 sm:py-0 sm:space-y-0 sm:divide-y sm:divide-accents-3 border-t border-accents-3">
-              {items.map((item) => (
+              {items.map((item: any) => (
                 <CartItem
                   key={item.id}
                   item={item}

components/common/Layout/Layout.tsx

@@ -9,9 +9,11 @@ import { useAcceptCookies } from '@lib/hooks/useAcceptCookies'
 import { Sidebar, Button, Modal, LoadingDots } from '@components/ui'
 import { CartSidebarView } from '@components/cart'
 
+import LoginView from '@components/auth/LoginView'
 import { CommerceProvider } from '@framework'
 import type { Page } from '@framework/api/operations/get-all-pages'
 
+
 const Loading = () => (
   <div className="w-80 h-80 flex items-center text-center justify-center p-3">
     <LoadingDots />
@@ -22,10 +24,6 @@ const dynamicProps = {
   loading: () => <Loading />,
 }
 
-const LoginView = dynamic(
-  () => import('@components/auth/LoginView'),
-  dynamicProps
-)
 const SignUpView = dynamic(
   () => import('@components/auth/SignUpView'),
   dynamicProps

components/ui/Modal/Modal.module.css

@@ -4,7 +4,7 @@
 }
 
 .modal {
-  @apply bg-primary p-12 border border-accents-2;
+  @apply bg-primary p-12 border border-accents-2 relative;
 }
 
 .modal:focus {

components/ui/Modal/Modal.tsx

@@ -1,4 +1,4 @@
-import { FC, useRef, useEffect } from 'react'
+import { FC, useRef, useEffect, useCallback } from 'react'
 import Portal from '@reach/portal'
 import s from './Modal.module.css'
 import { Cross } from '@components/icons'
@@ -7,45 +7,53 @@ import {
   enableBodyScroll,
   clearAllBodyScrollLocks,
 } from 'body-scroll-lock'
-
+import FocusTrap from '@lib/focus-trap'
 interface Props {
   className?: string
   children?: any
   open?: boolean
   onClose: () => void
+  onEnter?: () => void | null
 }
 
-const Modal: FC<Props> = ({ children, open, onClose }) => {
+const Modal: FC<Props> = ({ children, open, onClose, onEnter = null }) => {
   const ref = useRef() as React.MutableRefObject<HTMLDivElement>
 
+  const handleKey = (e: KeyboardEvent) =>
+    useCallback(() => {
+      if (e.key === 'Escape') {
+        return onClose()
+      }
+    }, [onClose])
+
   useEffect(() => {
     if (ref.current) {
       if (open) {
         disableBodyScroll(ref.current)
+        window.addEventListener('keydown', handleKey)
       } else {
         enableBodyScroll(ref.current)
       }
     }
     return () => {
+      window.removeEventListener('keydown', handleKey)
       clearAllBodyScrollLocks()
     }
-  }, [open])
+  }, [open, handleKey])
 
   return (
     <Portal>
       {open ? (
-        <div className={s.root} ref={ref}>
-          <div className={s.modal}>
-            <div className="h-7 flex items-center justify-end w-full">
-              <button
-                onClick={() => onClose()}
-                aria-label="Close panel"
-                className="hover:text-gray-500 transition ease-in-out duration-150 focus:outline-none"
-              >
-                <Cross className="h-6 w-6" />
-              </button>
-            </div>
-            {children}
+        <div className={s.root}>
+          <div className={s.modal} role="dialog" ref={ref}>
+            <button
+              onClick={() => onClose()}
+              aria-label="Close panel"
+              className="hover:text-gray-500 transition ease-in-out duration-150 focus:outline-none absolute right-0 top-0 m-6"
+            >
+              <Cross className="h-6 w-6" />
+            </button>
+            <FocusTrap focusFirst>{children}</FocusTrap>
           </div>
         </div>
       ) : null}

lib/focus-trap.tsx

@@ -0,0 +1,64 @@
+import React, { useEffect, RefObject } from 'react'
+import { tabbable } from 'tabbable'
+
+interface Props {
+  children: React.ReactNode | any
+  focusFirst?: boolean
+}
+
+export default function FocusTrap({ children, focusFirst = false }: Props) {
+  const root: RefObject<any> = React.useRef()
+  const anchor: RefObject<any> = React.useRef(document.activeElement)
+
+  const returnFocus = () => {
+    // Returns focus to the last focused element prior to trap.
+    if (anchor) {
+      anchor.current.focus()
+    }
+  }
+
+  const trapFocus = () => {
+    // Focus the container element
+    if (root.current) {
+      root.current.focus()
+      if (focusFirst) {
+        selectFirstFocusableEl()
+      }
+    }
+  }
+
+  const selectFirstFocusableEl = () => {
+    // Try to find focusable elements, if match then focus
+    // Up to 6 seconds of load time threshold
+    let match = false
+    let end = 60 // Try to find match at least n times
+    let i = 0
+    const timer = setInterval(() => {
+      if (!match !== i > end) {
+        match = !!tabbable(root.current).length
+        if (match) {
+          // Attempt to focus the first el
+          tabbable(root.current)[0].focus()
+        }
+        i = i + 1
+      } else {
+        // Clear interval after n attempts
+        clearInterval(timer)
+      }
+    }, 100)
+  }
+
+  useEffect(() => {
+    setTimeout(trapFocus, 20)
+    return () => {
+      returnFocus()
+    }
+  }, [root, children])
+
+  return React.createElement('div', {
+    ref: root,
+    children,
+    className: 'outline-none focus-trap',
+    tabIndex: -1,
+  })
+}

package.json

@@ -65,7 +65,8 @@
     "react-dom": "^16.14.0",
     "react-merge-refs": "^1.1.0",
     "react-ticker": "^1.2.2",
-    "swr": "^0.3.11",
+    "swr": "^0.4.0",
+    "tabbable": "^5.1.5",
     "tailwindcss": "^1.9"
   },
   "devDependencies": {

tailwind.config.js

@@ -8,6 +8,11 @@ module.exports = {
       './pages/**/*.{js,ts,jsx,tsx}',
       './components/**/*.{js,ts,jsx,tsx}',
     ],
+    options: {
+      safelist: {
+        standard: ['outline-none'],
+      },
+    },
   },
   theme: {
     extend: {