It should be deleteDoc, not updateDoc

[cbondoc]

snippets-web/snippets/firestore-next/test-firestore/update_delete_field.js

Lines 8 to 15 in 1abb6ce

	import { doc, updateDoc, deleteField } from "firebase/firestore";
	const cityRef = doc(db, 'cities', 'BJ');
	// Remove the 'capital' field from the document
	await updateDoc(cityRef, {
	capital: deleteField()
	});

[Nitinkumar-29]

The thing is you are updating a item in a collection but not deleting the item may be that's the reason they called it updateDoc instead of deleteDoc