Possible size reduction

[X-Ryl669]

In this code you can avoid the dom.remove() by simply doing dom.replaceWith('') So it can be replaced as let update = (dom, newDom) => newDom === dom || dom.replaceWith(newDom||'')

Also, there is many time the document variable in the script. Maybe it's worth creating an alias, since it won't be renamed by the minifier code, like this :

let dom = ns ? document.createElementNS(ns, name) : document.createElement(name)
// instead:
let d=document,dom = ns ? d.createElementNS(ns, name) : d.createElement(name)
// Or better:
let n = ns&&'NS', doc = document['createElement'+n](ns||name,name)

And finally, k.startsWith("on") appears twice in the same method, and is longer than an alias let o=k.startsWith('on') so it can be further optimized away.

Anyway, thanks for the library, it's very useful.