There is no way to patch element with id and classes without replacing it

There is no way to patch already existing element with classes and id, if root vnode also has id or classes.

var elm = document.createElement('div');
elm.setAttribute('id', 'testid');

var vnode = h('div#testid', 'testtext');
patch(elm, vnode);

console.log(elm === vnode.elm); // false
console.log(elm.innerText); // ''
console.log(vnode.elm.innerText); // 'testtext'

[paldepind]

Yes. The classes and id’s inside the selector are static. This has advantage that Snabbdom can use this static information exactly to determine if an element should be replaced. This makes using key unnecessary in many cases.

[grimalschi]

Ok, thank you!