I have been working on a navbar
functionality in next.js
. I have two functions (for the mobile interface of the website) that respectively close and open the navbar
, using a hamburger menu (for opening it) and an X icon on the navbar
(for closing it). These two functions are defined inside the page export (see code below) and update local variables defined in the page export, after which they are passed down as props to the hamburger component and the navbar
component.
The problem is that, upon changing the page from the navbar
, the variable (isNavbarOpen
) which holds the state of the navbar
, is not updated anymore through the hamburger menu and is only updated when I close the navbar
through the X icon inside of it.
The following is the index page function:
export default function Index() {
...
var navbarPlayingAnim = false;
var isNavbarOpen = false;
...
function openNavbar() {
var crntNavbarPos = -33;
function frame() {
if(crntNavbarPos >= 0) {
navbarPlayingAnim = false;
isNavbarOpen = true;
navbarRef.current!.style.left = "0";
clearInterval(AnimId)
}
else {
crntNavbarPos = crntNavbarPos + 33 * frameRate/(1000*navbarAnimDuration);
navbarRef.current!.style.left = String(crntNavbarPos) + "vw";
}
}
if(!navbarPlayingAnim && !isNavbarOpen) {
navbarPlayingAnim = true;
var AnimId = setInterval(frame,1000*navbarAnimDuration/frameRate);
}
}
function closeNavbar() {
var crntNavbarPos = 0;
function frame() {
if(crntNavbarPos <= -33) {
navbarRef.current!.style.left = "-33vw";
navbarPlayingAnim = false;
isNavbarOpen = false;
clearInterval(AnimId)
}
else {
crntNavbarPos = crntNavbarPos - 33* frameRate/(1000*navbarAnimDuration);
navbarRef.current!.style.left = String(crntNavbarPos) + "vw";
}
}
if(!navbarPlayingAnim && isNavbarOpen) {
navbarPlayingAnim = true;
var AnimId = setInterval(frame,1000*navbarAnimDuration/frameRate);
}
}
...
return(
...
<HamburgerBar openNavbarFunc={openNavbar}></HamburgerBar>
<NavBar changePage={changePage} navbarRef={navbarRef} mainRef={mainRef} titleRef={titleRef} aboutRef={aboutRef} serviceRef={serviceRef} contactRef={contactRef} closeNavbarFunc={closeNavbar}></NavBar>
...)
}
Hamburger menu function:
function HamburgerBar(props : {
openNavbarFunc : MouseEventHandler<HTMLDivElement>;
}) {
return (
<div onClick={props.openNavbarFunc} className={styles.hamburgerIcon}>
<ExportedImage src="/image/hamburger.png" alt="Hamburger logo" width={128} height={128} className={gC([styles.hamburgerImage,styles.unselectable])}></ExportedImage>
</div>
)
}
Navbar function:
function NavBar(props: {
navbarRef : RefObject<HTMLDivElement>,
mainRef : RefObject<HTMLDivElement>,
titleRef : RefObject<HTMLDivElement>,
aboutRef : RefObject<HTMLDivElement>,
serviceRef : RefObject<HTMLDivElement>,
contactRef : RefObject<HTMLDivElement>,
changePage : (targetPage: RefObject<HTMLDivElement>, targetIndex: number) => void;
closeNavbarFunc : MouseEventHandler<HTMLImageElement>
}) {
function NavBarButton(props: {
targetName : string;
targetRef : RefObject<HTMLDivElement>;
targetIndex : number;
mainRef : RefObject<HTMLDivElement>;
changePage : (targetPage: RefObject<HTMLDivElement>, targetIndex: number) => void;
closeNavbarFunc : MouseEventHandler<HTMLImageElement>
}) {
function goToPage() {
props.changePage(props.targetRef,props.targetIndex)
props.closeNavbarFunc;
}
return (
<div onClick={goToPage} className={styles.navbarButton}>
<a className={styles.unselectable}>{props.targetName}</a>
</div>
)
}
return (
<div ref={props.navbarRef} className={styles.navbar}>
<div className={styles.fill}>
<ExportedImage onClick={props.closeNavbarFunc} src="/image/x.png" alt="X Icon" width={64} height={64} className={styles.navbarX}></ExportedImage>
<ExportedImage src="/image/logo.png" alt="FuzzyHosting Logo" width={128} height={128} className={styles.navbarImage}></ExportedImage>
</div>
<NavBarButton changePage={props.changePage} closeNavbarFunc={props.closeNavbarFunc} targetName="Acasă" targetRef={props.titleRef} targetIndex={0} mainRef={props.mainRef}></NavBarButton>
<NavBarButton changePage={props.changePage} closeNavbarFunc={props.closeNavbarFunc} targetName="Despre noi" targetRef={props.aboutRef} targetIndex={1} mainRef={props.mainRef}></NavBarButton>
<NavBarButton changePage={props.changePage} closeNavbarFunc={props.closeNavbarFunc} targetName="Servicii" targetRef={props.serviceRef} targetIndex={2} mainRef={props.mainRef}></NavBarButton>
<NavBarButton changePage={props.changePage} closeNavbarFunc={props.closeNavbarFunc} targetName="Contact" targetRef={props.contactRef} targetIndex={3} mainRef={props.mainRef}></NavBarButton>
<div className={styles.fill}></div>
</div>
)
}
I defined the function for closing and opening the navbar inside the function for the index and passed them down as props. I expected them, upon being called in the functional components I passed them down to, to keep and update the variables defined inside the space where the openNavbar and closeNavbar functions were also defined, but this does not work.
Changing the page through the navbar menu and clicking the hamburger menu after that results in no change to the isNavbarOpen variable inside Index.
1
You have to use state
in order to hydrate your view. Using var
can surely chnage the value but it doesn’t re-render the DOM in React and Next. You have to make your code like:-
export default function Index() {
...
const [navbarPlayingAnim, setNavbarPlayingAnim] = useState(false);
const [isNavbarOpen, setIsNavbarOpen] = useState(false);
...
function openNavbar() {
var crntNavbarPos = -33;
function frame() {
if(crntNavbarPos >= 0) {
setNavbarPlayingAnim(false);
setIsNavbarOpen(true);
navbarRef.current!.style.left = "0";
clearInterval(AnimId)
}
else {
crntNavbarPos = crntNavbarPos + 33 * frameRate/(1000*navbarAnimDuration);
navbarRef.current!.style.left = String(crntNavbarPos) + "vw";
}
}
if(!navbarPlayingAnim && !isNavbarOpen) {
setNavbarPlayingAnim(true);
var AnimId = setInterval(frame,1000*navbarAnimDuration/frameRate);
}
}
function closeNavbar() {
var crntNavbarPos = 0;
function frame() {
if(crntNavbarPos <= -33) {
navbarRef.current!.style.left = "-33vw";
setNavbarPlayingAnim(false);
setIsNavbarOpen(false);
clearInterval(AnimId)
}
else {
crntNavbarPos = crntNavbarPos - 33* frameRate/(1000*navbarAnimDuration);
navbarRef.current!.style.left = String(crntNavbarPos) + "vw";
}
}
if(!navbarPlayingAnim && isNavbarOpen) {
setNavbarPlayingAnim(true);
var AnimId = setInterval(frame,1000*navbarAnimDuration/frameRate);
}
}
...
return(
...
<HamburgerBar openNavbarFunc={openNavbar}></HamburgerBar>
<NavBar changePage={changePage} navbarRef={navbarRef} mainRef={mainRef} titleRef={titleRef} aboutRef={aboutRef} serviceRef={serviceRef} contactRef={contactRef} closeNavbarFunc={closeNavbar}></NavBar>
...)
}
Make sure to replace all your hydrating logic accordingly.
1