Add custom scroll function

Author: rafgraph

src/index.js

@@ -5,6 +5,7 @@ import { Link, NavLink } from 'react-router-dom';
 let hashFragment = '';
 let observer = null;
 let asyncTimerId = null;
+let scrollFunction = null;
 
 function reset() {
   hashFragment = '';
@@ -18,7 +19,7 @@ function reset() {
 function getElAndScroll() {
   const element = document.getElementById(hashFragment);
   if (element !== null) {
-    element.scrollIntoView();
+    scrollFunction(element);
     reset();
     return true;
   }
@@ -60,7 +61,13 @@ export function genericHashLink(props, As) {
     ) {
       hashFragment = props.to.hash.replace('#', '');
     }
-    if (hashFragment !== '') hashLinkScroll();
+    if (hashFragment !== '') {
+      scrollFunction =
+        props.scroll ||
+        (el =>
+          el.scrollIntoView(props.smooth ? { behavior: 'smooth' } : undefined));
+      hashLinkScroll();
+    }
   }
   return (
     <As {...props} onClick={handleClick}>
@@ -80,6 +87,7 @@ export function NavHashLink(props) {
 const propTypes = {
   onClick: PropTypes.func,
   children: PropTypes.node,
+  scroll: PropTypes.func,
   to: PropTypes.oneOfType([PropTypes.string, PropTypes.object]),
 };