feat(JumpLinks): support passing a reference to scroll element

packages/react-core/src/components/JumpLinks/JumpLinks.tsx

@@ -21,7 +21,9 @@ export interface JumpLinksProps extends Omit<React.HTMLProps<HTMLElement>, 'labe
   alwaysShowLabel?: boolean;
   /** Adds an accessible label to the internal nav element. Defaults to the value of the label prop. */
   'aria-label'?: string;
-  /** Selector for the scrollable element to spy on. Not passing a selector disables spying. */
+  /** Reference to the scrollable element to spy on. Takes precedence over scrollableSelector. Not passing a scrollableRef or scrollableSelector disables spying. */
+  scrollableRef?: HTMLElement | (() => HTMLElement) | React.RefObject<HTMLElement>;
+  /** Selector for the scrollable element to spy on. Not passing a scrollableSelector or scrollableRef disables spying. */
   scrollableSelector?: string;
   /** The index of the child Jump link to make active. */
   activeIndex?: number;
@@ -81,6 +83,7 @@ export const JumpLinks: React.FunctionComponent<JumpLinksProps> = ({
   children,
   label,
   'aria-label': ariaLabel = typeof label === 'string' ? label : null,
+  scrollableRef,
   scrollableSelector,
   activeIndex: activeIndexProp = 0,
   offset = 0,
@@ -91,18 +94,29 @@ export const JumpLinks: React.FunctionComponent<JumpLinksProps> = ({
   className,
   ...props
 }: JumpLinksProps) => {
-  const hasScrollSpy = Boolean(scrollableSelector);
+  const hasScrollSpy = Boolean(scrollableRef || scrollableSelector);
   const [scrollItems, setScrollItems] = React.useState(hasScrollSpy ? getScrollItems(children, []) : []);
   const [activeIndex, setActiveIndex] = React.useState(activeIndexProp);
   const [isExpanded, setIsExpanded] = React.useState(isExpandedProp);
   // Boolean to disable scroll listener from overriding active state of clicked jumplink
   const isLinkClicked = React.useRef(false);
-  // Allow expanding to be controlled for a niche use case
-  React.useEffect(() => setIsExpanded(isExpandedProp), [isExpandedProp]);
   const navRef = React.useRef<HTMLElement>();
 
   let scrollableElement: HTMLElement;
 
+  const getScrollableElement = () => {
+    if (scrollableRef) {
+      if (scrollableRef instanceof HTMLElement) {
+        return scrollableRef;
+      } else if (typeof scrollableRef === 'function') {
+        return scrollableRef();
+      }
+      return (scrollableRef as React.RefObject<HTMLElement>).current;
+    } else if (scrollableSelector) {
+      return document.querySelector(scrollableSelector) as HTMLElement;
+    }
+  };
+
   const scrollSpy = React.useCallback(() => {
     if (!canUseDOM || !hasScrollSpy || !(scrollableElement instanceof HTMLElement)) {
       return;
@@ -139,14 +153,14 @@ export const JumpLinks: React.FunctionComponent<JumpLinksProps> = ({
   }, [scrollItems, hasScrollSpy, scrollableElement, offset]);
 
   React.useEffect(() => {
-    scrollableElement = document.querySelector(scrollableSelector) as HTMLElement;
+    scrollableElement = getScrollableElement();
     if (!(scrollableElement instanceof HTMLElement)) {
       return;
     }
     scrollableElement.addEventListener('scroll', scrollSpy);
 
     return () => scrollableElement.removeEventListener('scroll', scrollSpy);
-  }, [scrollableSelector, scrollSpy]);
+  }, [scrollableElement, scrollSpy, getScrollableElement]);
 
   React.useEffect(() => {
     scrollSpy();
@@ -174,7 +188,7 @@ export const JumpLinks: React.FunctionComponent<JumpLinksProps> = ({
 
                 if (newScrollItem) {
                   // we have to support scrolling to an offset due to sticky sidebar
-                  const scrollableElement = document.querySelector(scrollableSelector) as HTMLElement;
+                  const scrollableElement = getScrollableElement() as HTMLElement;
                   if (scrollableElement instanceof HTMLElement) {
                     if (isResponsive(navRef.current)) {
                       // Remove class immediately so we can get collapsed height

packages/react-core/src/demos/JumpLinks.md

@@ -9,9 +9,10 @@ import mastheadStyles from '@patternfly/react-styles/css/components/Masthead/mas
 
 JumpLinks has a scrollspy built-in to make your implementation easier. When implementing JumpLinks be sure to:
 
-1. Find the correct `scrollableSelector` for your page via [Firefox's debugging scrollable overflow](https://developer.mozilla.org/en-US/docs/Tools/Page_Inspector/How_to/Debug_Scrollable_Overflow) or by adding `hasOverflowScroll` to a [PageSection](/components/page#pagesection) or [PageGroup](/components/page#pagegroup).
+1. Find the correct scrollable element for your page via [Firefox's debugging scrollable overflow](https://developer.mozilla.org/en-US/docs/Tools/Page_Inspector/How_to/Debug_Scrollable_Overflow) or by adding `hasOverflowScroll` to a [PageSection](/components/page#pagesection) or [PageGroup](/components/page#pagegroup).
    - If you add `hasOverflowScroll` to a Page sub-component you should also add a relevant aria-label to that component as well.
-2. Provide `href`s to your JumpLinksItems which match the `id` of elements you want to spy on. If you wish to scroll to a different item than you're linking to use the `node` prop.
+2. Provide a reference to the scrollable element to `scrollableRef` prop or a CSS selector of the scrollable element to `scrollableSelector` prop.
+3. Provide `href`s to your JumpLinksItems which match the `id` of elements you want to spy on. If you wish to scroll to a different item than you're linking to use the `node` prop.
 
 ### Scrollspy with subsections
 
@@ -141,7 +142,7 @@ ScrollspyH2 = () => {
 
 This demo shows how jump links can be used in combination with a drawer.
 
-The `scrollableSelector` prop passed to the jump links component is an `id` that was placed on the `DrawerContent` component.
+This demo uses a `scrollableRef` prop on the JumpLinks component, which is a React ref to the `DrawerContent` component.
 
 ```js isFullscreen file="./examples/JumpLinks/JumpLinksWithDrawer.js"
 ```

packages/react-core/src/demos/examples/JumpLinks/JumpLinksWithDrawer.js

@@ -17,11 +17,33 @@ import {
   SidebarContent,
   SidebarPanel,
   TextContent,
-  getResizeObserver
+  getResizeObserver,
+  DrawerContext
 } from '@patternfly/react-core';
 import { DashboardWrapper } from '@patternfly/react-core/src/demos/DashboardWrapper';
 import mastheadStyles from '@patternfly/react-styles/css/components/Masthead/masthead';
 
+const JumpLinksWrapper = ({ offsetHeight, headings }) => {
+  const { drawerContentRef } = React.useContext(DrawerContext);
+
+  return (
+    <JumpLinks
+      isVertical={true}
+      label="Jump to section"
+      scrollableRef={drawerContentRef}
+      offset={offsetHeight}
+      expandable={{ default: 'expandable', md: 'nonExpandable' }}
+    >
+      {headings.map((heading) => (
+        <JumpLinksItem key={heading} href={`#jump-links-drawer-jump-links-${heading.toLowerCase()}`}>
+          {`${heading} section`}
+          <JumpLinksList></JumpLinksList>
+        </JumpLinksItem>
+      ))}
+    </JumpLinks>
+  );
+};
+
 export const JumpLinksWithDrawer = () => {
   const headings = ['First', 'Second', 'Third', 'Fourth', 'Fifth'];
 
@@ -66,25 +88,12 @@ export const JumpLinksWithDrawer = () => {
   return (
     <DashboardWrapper breadcrumb={null} mainContainerId="scrollable-element">
       <Drawer isExpanded={isExpanded}>
-        <DrawerContent panelContent={panelContent} id="jump-links-drawer-drawer-scrollable-container">
+        <DrawerContent panelContent={panelContent}>
           <DrawerContentBody>
             <Sidebar>
               <SidebarPanel variant="sticky">
                 <PageSection variant={PageSectionVariants.light}>
-                  <JumpLinks
-                    isVertical={true}
-                    label="Jump to section"
-                    scrollableSelector="#jump-links-drawer-drawer-scrollable-container"
-                    offset={offsetHeight}
-                    expandable={{ default: 'expandable', md: 'nonExpandable' }}
-                  >
-                    {headings.map((heading) => (
-                      <JumpLinksItem key={heading} href={`#jump-links-drawer-jump-links-${heading.toLowerCase()}`}>
-                        {`${heading} section`}
-                        <JumpLinksList></JumpLinksList>
-                      </JumpLinksItem>
-                    ))}
-                  </JumpLinks>
+                  <JumpLinksWrapper offsetHeight={offsetHeight} headings={headings} />
                 </PageSection>
               </SidebarPanel>
               <SidebarContent>