V1: instanceof operator isn't working for non-patched nodes.

[blasten]

Using the v1, the following assertion fails:

assert.isTrue(document.documentElement instenceof HTMLElement);

/cc @justinfagnani

[blasten]

I also found that HTMLElement.ELEMENT_NODE is undefined.

[justinfagnani]

The first issue is more or less unsolvable. Any element that has HTMLElement as its direct prototype can't be patched to make instanceof work.

The second issue is fixable and important. We need to copy statics down.

[shannonmoeller]

In case it's useful to others, my team came up with a workaround. It's far from perfect, but it worked well enough for our needs:

const div = document.createElement('div');

console.log((/^HTML\w*Element/).test(div.constructor.name));

Further, all of our custom element use a specific prefix, so we could extend the regex to:

/^(HTML|Foo)\w*Element/

[justinfagnani]

For your custom elements, instanceof should work fine. The issue here is that the polyfilled HTMLElement's prototype isn't on the prototype chain of the built-in elements, but your custom element's prototype is fine.

Another option, which should be fine in basically all cases, is el.nodeType === Node.ELEMENT_NODE.

[blasten]

thanks for the reply @justinfagnani

[notwaldorf]

This sounds like a CustomElements polyfill issue so I'm moving it there, sorrynotsorry.

[notwaldorf]

This issue was moved to webcomponents/custom-elements#48