I came across a problem where I had to find the ES6 features used by any javascript project and other data regarding their use. When I reached out to stackoverflow, I could find only one relevant post which asks you to use linters like jshint/jshint or compilers like babel. Jslint didn't seem to report anything specific to ES6 and Babel converts all the ES6+ features to ES5 but doesn't report anything regarding which constructs were used or how many times they were used. However, Jshint reported all ES6 features used in the code along with some metadata. And, to suit my needs, I ended up writing a python script that calls Jshint on all JS files in a project and presents the features used in the project and the number of times they were used across all files. You can find the code here : jsHintRunner

Feel free to report a bug/issue or open a PR if you have improvement ideas.

Hope this helps someone at some point.