DVV,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<div id="linkContainer">
<a data-href="https://link1" class="js-additional-link">Ссылка 1</a>
<a data-href="https://link2" class="js-additional-link">Ссылка 2</a>
</div>
<input type="text" id="text" value="есть такая">
<input type="text" id="link" value="https://link1">
<button id="add">Добавить</button>
<script>
const btnAdd = document.getElementById('add');
const linkContainer = document.getElementById('linkContainer');
const txt = document.getElementById('text');
const lnk = document.getElementById('link');
function checLinksForMatches() {
const boxLinkNames = document.querySelectorAll('.js-additional-link');
const text = txt.value;
const link = lnk.value;
if(!text || !link) return;
let add = true;
for (let mainLink of boxLinkNames) {
if (mainLink.dataset.href === link) {
console.log('равна');
add = false;
break;
}
}
if (add) {
console.log('Не равна');
const newLink = document.createElement('a');
newLink.dataset.href = link;
newLink.textContent = text;
newLink.classList.add('js-additional-link');
linkContainer.append(newLink);
txt.value = '';
lnk.value = '';
}
}
btnAdd.addEventListener('click', checLinksForMatches);
</script>
</body>
</html>