From 363c7d621b1faeb7067cd1ead4039821f0e1c888 Mon Sep 17 00:00:00 2001
From: Peter Sieg <peter.sieg@appfolio.com>
Date: Mon, 22 Apr 2024 18:20:27 -0400
Subject: [PATCH] feat(APT-1610): add portalEl prop to Combobox

This allows space/position constrained implementations of combobox to render the dropdown menu in another component so the positioning of the menu is not dependent on the parent element.
---
 src/components/Combobox/Combobox.spec.js    | 17 ++++++++-
 src/components/Combobox/Combobox.stories.js | 20 ++++++++++
 src/components/Combobox/Combobox.tsx        | 42 ++++++++++++---------
 3 files changed, 60 insertions(+), 19 deletions(-)

diff --git a/src/components/Combobox/Combobox.spec.js b/src/components/Combobox/Combobox.spec.js
index 7e6ce4c53..9741ce7a7 100644
--- a/src/components/Combobox/Combobox.spec.js
+++ b/src/components/Combobox/Combobox.spec.js
@@ -1,5 +1,5 @@
 import assert from 'assert';
-import { render, fireEvent, cleanup } from '@testing-library/react';
+import { render, fireEvent, cleanup, screen, within } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 import React from 'react';
 import sinon from 'sinon';
@@ -361,6 +361,21 @@ describe('<Combobox />', () => {
     );
   });
 
+  it('can render the dropdown menu inside a portal', async () => {
+    render(<Combobox options={OPTIONS} portalEl={document.body} />);
+    const toggle = await screen.findByTestId('react-gears-combobox-button');
+    await userEvent.click(toggle);
+    const dropdown = await screen.findByTestId('react-gears-combobox-dropdownmenu');
+
+    expect(dropdown.parentElement).toEqual(document.body);
+
+    expect(
+      within(await screen.findByTestId('react-gears-combobox-dropdown')).queryByTestId(
+        'react-gears-combobox-dropdownmenu'
+      )
+    ).toBeNull();
+  });
+
   describe('default filterOptions ', () => {
     it('should filter by input (case insensitive)', () => {
       const combobox = render(<Combobox options={OPTIONS} />);
diff --git a/src/components/Combobox/Combobox.stories.js b/src/components/Combobox/Combobox.stories.js
index 7a3d17c60..c51e96b5d 100644
--- a/src/components/Combobox/Combobox.stories.js
+++ b/src/components/Combobox/Combobox.stories.js
@@ -203,3 +203,23 @@ export const CustomOptions = () => {
     />
   );
 };
+
+export const PortalElement = () => {
+  const [value, setValue] = useState();
+  return (
+    <>
+      <div>value: {value}</div>
+      <Combobox
+        direction={select('direction', ['', 'down', 'up'], '')}
+        onChange={setValue}
+        options={options}
+        value={value}
+        disabled={boolean('disabled', Combobox.defaultProps.disabled)}
+        noResultsLabel={text('noResultsLabel', Combobox.defaultProps.noResultsLabel)}
+        placeholder={text('placeholder', Combobox.defaultProps.placeholder)}
+        inputClassName={text('inputClassName', '')}
+        portalEl={document.body}
+      />
+    </>
+  );
+};
diff --git a/src/components/Combobox/Combobox.tsx b/src/components/Combobox/Combobox.tsx
index eceb05466..4a88e5c31 100644
--- a/src/components/Combobox/Combobox.tsx
+++ b/src/components/Combobox/Combobox.tsx
@@ -1,6 +1,6 @@
 import equal from 'fast-deep-equal';
 import React, { useEffect, useState, useRef, useMemo } from 'react';
-import { findDOMNode } from 'react-dom';
+import { createPortal, findDOMNode } from 'react-dom';
 import { DropdownProps, InputProps } from 'reactstrap';
 import Badge from '../Badge/Badge';
 import Button from '../Button/Button';
@@ -37,6 +37,7 @@ interface ComboboxProps<T> extends Omit<InputProps, 'onChange'> {
   renderOption?: (option: Option<T>) => React.ReactNode;
   menuMaxHeight?: string;
   multi?: boolean;
+  portalEl?: HTMLElement;
 }
 
 const defaultProps = {
@@ -60,6 +61,7 @@ function Combobox<T>({
   menuMaxHeight,
   multi,
   noResultsLabel = defaultProps.noResultsLabel,
+  portalEl,
   onChange = defaultProps.onChange,
   onCreate,
   isValidNewOption = defaultProps.isValidNewOption,
@@ -118,7 +120,7 @@ function Combobox<T>({
 
     if (open && !multi && selected && inputElement?.current) {
       window.setTimeout(() => {
-        inputElement!.current!.setSelectionRange(0, 0);
+        inputElement!.current?.setSelectionRange(0, 0);
       }, 1);
     }
   }, [open, multi, selected]);
@@ -332,6 +334,25 @@ function Combobox<T>({
     return <DropdownItem disabled>{noResultsLabel}</DropdownItem>;
   };
 
+  const menu = (
+    <DropdownMenu
+      data-testid="react-gears-combobox-dropdownmenu"
+      className="p-0 w-100"
+      style={{ maxHeight: menuMaxHeight || '12rem', overflowY: 'auto' }}
+      {...dropdownProps}
+      ref={dropdownMenu}
+      role="listbox"
+      aria-activedescendant={
+        visibleOptions[focusedOptionIndex] &&
+        `option-${JSON.stringify(visibleOptions[focusedOptionIndex].value)}`
+      }
+      aria-multiselectable={multi}
+    >
+      {grouped ? renderGroupedOptions(optionsProp as OptionGroup<T>[]) : renderOptions(options)}
+      {noMatches && renderNoOptions()}
+    </DropdownMenu>
+  );
+
   return (
     <>
       {multi && (selected as Option<T>[]).length > 0 && (
@@ -442,22 +463,7 @@ function Combobox<T>({
             </Button>
           </InputGroup>
         </DropdownToggle>
-        <DropdownMenu
-          data-testid="react-gears-combobox-dropdownmenu"
-          className="p-0 w-100"
-          style={{ maxHeight: menuMaxHeight || '12rem', overflowY: 'auto' }}
-          {...dropdownProps}
-          ref={dropdownMenu}
-          role="listbox"
-          aria-activedescendant={
-            visibleOptions[focusedOptionIndex] &&
-            `option-${JSON.stringify(visibleOptions[focusedOptionIndex].value)}`
-          }
-          aria-multiselectable={multi}
-        >
-          {grouped ? renderGroupedOptions(optionsProp as OptionGroup<T>[]) : renderOptions(options)}
-          {noMatches && renderNoOptions()}
-        </DropdownMenu>
+        {portalEl ? <div>{createPortal(menu, portalEl)}</div> : menu}
       </Dropdown>
     </>
   );