Added scroll based menu highlight feature (#1085)

Co-authored-by: Beier (Bill) <[email protected]>

Author: Tiru-99

src/components/Menu/Menu.tsx

@@ -1,13 +1,50 @@
+import { useEffect, useState } from "react"
 import Link from "next/link"
-import colors from "../../styles/colors"
 import styles from "./SideMenu.module.css"
 import typographyStyles from "../../styles/typography.module.css"
-import { useRouter } from "next/router"
+import colors from "../../styles/colors"
 import { Pages } from "../../types/types"
 
 function Menu({ pages = [] }: { pages: Pages }) {
-  const router = useRouter()
-  const { asPath: pathname } = router
+  const [activeSection, setActiveSection] = useState<string>("")
+
+  useEffect(() => {
+    const handleScroll = () => {
+      const sections = pages.flatMap((page) =>
+        [page, ...(page.pages || [])].map((p) => ({
+          id: p.pathname.replace("#", ""),
+          top:
+            document.getElementById(p.pathname.replace("#", ""))?.offsetTop ||
+            0,
+        }))
+      )
+
+      const currentSection = sections.reduce((acc, section) => {
+        const { id, top } = section
+        if (window.scrollY >= top - 100) {
+          console.log(id)
+          return id
+        }
+        return acc
+      }, "")
+
+      setActiveSection(currentSection)
+    }
+
+    window.addEventListener("scroll", handleScroll)
+
+    handleScroll()
+
+    return () => window.removeEventListener("scroll", handleScroll)
+  }, [pages])
+
+  const scrollToSection = (sectionId: string, event: React.MouseEvent) => {
+    event.preventDefault()
+    const element = document.getElementById(sectionId.replace("#", ""))
+    if (element) {
+      element.scrollIntoView({ behavior: "smooth" })
+    }
+  }
 
   return (
     <aside className={styles.menu}>
@@ -26,41 +63,57 @@ function Menu({ pages = [] }: { pages: Pages }) {
 
         <ul className="scrollArea">
           {pages.map((page) => {
-            const isActive = pathname === page.pathname
+            const isActive = activeSection === page.pathname.replace("#", "")
+            const hasActiveChild = page.pages?.some(
+              (subPage) => activeSection === subPage.pathname.replace("#", "")
+            )
 
             return (
               <li
                 key={page.pathname}
-                className={styles.menuItem}
+                className={`${styles.menuItem} ${
+                  isActive || hasActiveChild ? styles.activeParent : ""
+                }`}
                 style={{
                   display: page?.pages ? "block" : "flex",
                 }}
               >
-                <code aria-hidden className={styles.code}>{`</>`}</code>
-                <Link
-                  className={isActive ? styles.isActive : ""}
+                <code aria-hidden className={styles.code}>
+                  {`</>`}
+                </code>
+                <a
                   href={page.pathname}
+                  className={isActive ? styles.isActive : ""}
+                  onClick={(e) => scrollToSection(page.pathname, e)}
                 >
                   {page.name}
-                </Link>
+                </a>
 
                 {page?.pages && (
                   <ul>
-                    {page.pages.map((page) => {
-                      const isActive = pathname === page.pathname
+                    {page.pages.map((subPage) => {
+                      const isSubActive =
+                        activeSection === subPage.pathname.replace("#", "")
 
                       return (
-                        <li key={page.pathname} className={styles.menuItem}>
-                          <code
-                            aria-hidden
-                            className={styles.code}
-                          >{`</>`}</code>{" "}
-                          <Link
-                            className={isActive ? styles.isActive : ""}
-                            href={page.pathname}
+                        <li
+                          key={subPage.pathname}
+                          className={`${styles.menuItem} ${
+                            isSubActive ? styles.activeItem : ""
+                          }`}
+                        >
+                          <code aria-hidden className={styles.code}>
+                            {`</>`}
+                          </code>
+                          <a
+                            href={subPage.pathname}
+                            className={isSubActive ? styles.isActive : ""}
+                            onClick={(e) =>
+                              scrollToSection(subPage.pathname, e)
+                            }
                           >
-                            {page.name}
-                          </Link>
+                            {subPage.name}
+                          </a>
                         </li>
                       )
                     })}