Svelte - change the style of a nav-item when clicked - svelte-3

Question

I'm using Bulma CSS to create a nav component in Svelte and I would like to make each navbar-item bold when class:is-active is true. What I have currently done is follows:
<script>
import {onMount} from 'svelte';
let segment;
onMount(() => {
const linkOne = document.getElementById("linkOne");
const linkTwo = document.getElementById("linkTwo");
const linkThree = document.getElementById("linkThree");
const linkFour = document.getElementById("linkFour");
const linkFive = document.getElementById("linkFive");
linkOne.addEventListener('focusin', (event) => {
event.target.style["font-weight"] = 'bold';
});
linkOne.addEventListener('blur', (event) => {
event.target.style["font-weight"] = 'normal';
});
linkTwo.addEventListener('focusin', (event) => {
event.target.style["font-weight"] = 'bold';
});
linkTwo.addEventListener('blur', (event) => {
event.target.style["font-weight"] = 'normal';
});
linkThree.addEventListener('focusin', (event) => {
event.target.style["font-weight"] = 'bold';
});
linkThree.addEventListener('blur', (event) => {
event.target.style["font-weight"] = 'normal';
});
linkFour.addEventListener('focusin', (event) => {
event.target.style["font-weight"] = 'bold';
});
linkFour.addEventListener('blur', (event) => {
event.target.style["font-weight"] = 'normal';
});
linkFive.addEventListener('focusin', (event) => {
event.target.style["font-weight"] = 'bold';
});
linkFive.addEventListener('blur', (event) => {
event.target.style["font-weight"] = 'normal';
});
});
</script>
<nav class="navbar" role="navigation" aria-label="main navigation">
<div class="navbar-brand">
<a href="/" class="navbar-item">
</a>
</div>
<div class="nav-menubar">
<div class="navbar-menu">
<a id="linkOne" href="/" class="navbar-item" class:is-active={segment === undefined}>LinkOne</a>
<a id="linkTwo" href="/linkTwo" class="navbar-item" class:is-active={segment === "linktwo"}>LinkTwo</a>
<a id="linkThree" href="/linkThree" class="navbar-item" class:is-active={segment === "linkthree"}>LinkThree</a>
<a id="linkFour" href="/linkFour" class="navbar-item" class:is-active={segment === "linkfour"}>LinkFour</a>
<a id="linkFive" href="/linkFive" class="navbar-item" class:is-active={segment === "linkfive"}> LinkFive</a>
</div>
</div>
</nav>
On Firefox(81.0), this results in a link becoming bold onFocus but when switching to another link and back, the same link doesn't become bold unless clicked twice. Also, I am not certain that this is the best way to set the style for these components. Can someone suggest a better way to do this?

Answer 1

You can achieve it easily in Svelte:
<script>
let current = 0;
</script>
<a
on:click="{() => current = 1}"
class:active="{current === 1}"
>Number 1</a>
<a
on:click="{() => current = 2}"
class:active="{current === 2}"
>Number 2</a>
<a
on:click="{() => current = 3}"
class:active="{current === 3}"
>Number 3</a>
<style>
a {
display: block;
}
.active {
color: rgb(255, 133, 34);
font-weight: bolder;
}
</style>
Also you can learn more on: https://svelte.dev/tutorial/classes

Answer 2

You can replace all that JavaScript with one simple CSS rule instead:
a:focus {
font-weight: bold;
}