To learn more about the new features added in earlier WebStorm 2017.3 EAP builds, please see these blog posts.
Previously we used and maintained our own definition files. Thanks to the transition to the new definition files, WebStorm now provides code completion for Web APIs that were previously unsupported.
Another good news is that the new definition files have documentation for many methods (which you can see if you press F1). If the documentation if not available there, WebStorm will fetch and show the summary from the corresponding MDN article.
From the documentation popup, you can quickly jump to the full documentation on MDN by clicking the arrow icon. Or you can go directly to it from the code by pressing Shift-F1. Continue reading