title: Javascript: Is there an equivalent to caniuse.com for HTML5 APIs/ECMAScript5/ECMAScript6 in the various browsers?
body: <p>Is there an equivalent to caniuse.com for HTML5 APIs / ECMAScript5 / ECMAScript6 in the various browsers?</p>
  
  <p>caniuse.com does have some javascript coverage, but pages like <a href="http://caniuse.com/#feat=filesystem">http://caniuse.com/#feat=filesystem</a> don't really tell you anything other than yes/no/partially.  Realistically, I'm looking for something like quirksmode crossed with caniuse, where I could look in detail at any API or method and see where it is currently implemented (and bug free).  A site where, for example, I could look and see which versions of which browsers will currently work with this:</p>
  
  <pre><code>Object.keys(CONSTANTS.TEXT).forEach(function(key) {
      languages.push([key, CONSTANTS.TEXT[key].languageName]);
  });
  </code></pre>