How to style Link component when on active page on Next.js

Question

I have a question about styling an anchor component when it is on the active page.

Here is my code:

import Link from 'next/link';
import styled from 'styled-components';

const NavStyle = styled.nav`
    display: flex;
    justify-content: space-between;
    .nav-link a {
        text-decoration: none;
        color: white;
        padding: 10px;
        background-color: #FFCF00;
    }
`;

export default function Nav() {
    return (
        <NavStyle>
            <div className="nav-link">
                <Link href="/" passHref>
                    <a>HOME</a>
                </Link>
                <Link href="/pricing">
                    <a>PRICING</a>
                </Link>
                <Link href="/terms">
                    <a>TERMS</a>
                </Link>
                <Link href="/login">
                    <a>LOGIN</a>
                </Link>
            </div>
            <Link href="/">
                <a>LOGO</a>
            </Link>
        </NavStyle>
    )
}

What I want is, when the I click on the link and move to another page, the active link (that's matched with the URL) would have a green background. I have tried this, but it doesn't make any change:

const NavStyle = styled.nav`
    display: flex;
    justify-content: space-between;
    .nav-link a {
        text-decoration: none;
        color: white;
        padding: 10px;
        background-color: #FFCF00;
        &[aria-current] {
          background-color: green;
       }
    }
`;

Answer 1

Next.js won't add aria-current to your active link; however, you can create a custom Link component that checks if the current pathname is the same as the href prop.

import React from "react";
import Link from "next/link";
import { useRouter } from "next/router";

const NavLink = ({ children, href }) => {
  const child = React.Children.only(children);
  const router = useRouter();

  return (
    <Link href={href}>
      {React.cloneElement(child, {
        "aria-current": router.pathname === href ? "page" : null
      })}
    </Link>
  );
};

export default NavLink;

Then, you can use this component instead of the default Link whenever you want to add aria-current to the active link:

const NavStyle = styled.nav`
  display: flex;
  justify-content: space-between;

  a {
    background-color: #353637;
    color: #fff;
    padding: 1rem;
    text-decoration: none;

    &[aria-current] {
      background-color: #faf9f4;
      color: #353637;
    }
  }
`;

export default function Nav() {
  return (
    <NavStyle>
      <div className="nav-link">
        <NavLink href="/">
          <a>HOME</a>
        </NavLink>
        <NavLink href="/pricing">
          <a>PRICING</a>
        </NavLink>
        <NavLink href="/terms">
          <a>TERMS</a>
        </NavLink>
        <NavLink href="/login">
          <a>LOGIN</a>
        </NavLink>
      </div>
      <Link href="/">
        <a>LOGO</a>
      </Link>
    </NavStyle>
  );
}