Chrome 49 boasts 91% ES6 support
In V8 release 4.9 we shipped more JavaScript ES2015 features than in any other previous release, bringing us to 91% completion as measured by the Kangax compatibility table (as of January 26). V8 now supports destructuring, default parameters, Proxy objects, and the Reflect API.
Release 4.9 also makes block level constructs such as class and let available outside of strict mode and adds support for the sticky flag on regular expressions and customizable Object.prototype.toString output.
Read more from the source: v8project.blogspot.com