Fixes issue #183

[ricksbrown]

Actually this is a workaround, not a fix because the bug is in closure compiler. I'll break it down in detail below.

First understand that the function axs.properties.findTextAlternatives can legitimately return null.
Then take a look at the way we call it:

var textAlternatives = axs.properties.findTextAlternatives(element, {});
if (!textAlternatives || textAlternatives.trim() === '')

All good. But then take a look at what closure compiler produces:

return "" === axs.properties.findTextAlternatives(a, {}).trim() ? !1 : !0;

That will throw an exception if the return value is null.
The easiest workaround is to get closure compiler to produce something else. The proposed change does not change the logic of the audit but results in safe code generated by closure compiler:

a = axs.properties.findTextAlternatives(a, {});
  return null == a || "" === a.trim() ? !1 : !0;

[ricksbrown]

@alice PTAL

[alice]

Let's use === null - closure compile should catch if findTextAlternatives weirdly returns undefined anywhere.

[alice]

Please update the Changelog: https://github.com/GoogleChrome/accessibility-developer-tools/blob/master/Changelog.md - manual process to help me write release notes. Sorry for the overhead :(

Once that's done and the nit addressed, this is 👍 - definitely an improvement regardless of the closure weirdness.

[ricksbrown]

No worries about the changelog overhead, it is well worth the effort IMHO.