Javascript: Is there an equivalent to caniuse.com for HTML5 APIs/ECMAScript5/ECMAScript6 in the various browsers?

Question

Is there an equivalent to caniuse.com for HTML5 APIs / ECMAScript5 / ECMAScript6 in the various browsers?

caniuse.com does have some javascript coverage, but pages like http://caniuse.com/#feat=filesystem 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:

Object.keys(CONSTANTS.TEXT).forEach(function(key) {
    languages.push([key, CONSTANTS.TEXT[key].languageName]);
});

Answer 1

Just found something like this in the references to a different question. ES5: http://kangax.github.com/es5-compat-table/ ES6: http://kangax.github.com/es5-compat-table/es6/ nonstandardized: http://kangax.github.com/es5-compat-table/non-standard/