Elements failing instanceof after WebComponentsReady

[jyasskin]

http://jeffrey.yasskin.info/dump/instanceof_test.html (code at https://gist.github.com/jyasskin/8575145) shows "Tag Name: CXX-FUNCTION; Instance of CxxFunctionElement: false" despite the element being registered with <polymer-element name="cxx-function" constructor="CxxFunctionElement" noscript>.

Oddly, copying the same code into a jsbin does not reproduce the problem. It has to run directly on a server. This is in Mac Chrome 34.0.1797.2 with none of the experimental flags turned on. On Canary with --enable-experimental-web-platform-features, the problem also doesn't happen, which makes me suspect the shadow dom polyfill wrapper objects.

[sjmiles]

Confirm behavior is different between Firefox and Chrome, although I don't know exactly what polyfill or interaction is the root cause.

[sorvell]

@jmesserly Would you mind taking a look at this? Thanks.

[jmesserly]

this looks like it was fixed to me. I'm now seeing the same result on Chrome/Firefox using a local server. (CxxFunctionElement: true)

for what it's worth, I think domReady is the callback you're looking for:

      Polymer('cxx-section', {
          domReady: function() {
              var child = this.firstElementChild;
              this.tag_name = child.tagName;
              this.instance = child instanceof CxxFunctionElement;
          },
      });

docs here: http://www.polymer-project.org/docs/polymer/polymer.html#lifecyclemethods

[jmesserly]

tentatively going to close assuming this is fixed, let me know if you see it crop up again. Cheers!