I have already replaced all JavaScript with Go (by using GopherJS compiler) in my personal projects, as of about a year ago.
I am really enjoying it and I don't see myself going back to writing JavaScript by hand anytime soon. I use it to do some frontend stuff that involves DOM manipulation, XHRs, WebSockets. Another use is WebGL, it allows me to write simple multi-platform games in Go that target OS X, Linux, Windows, but also the browser. I would not be writing those games in JavaScript by a long shot.
I am really enjoying it and I don't see myself going back to writing JavaScript by hand anytime soon. I use it to do some frontend stuff that involves DOM manipulation, XHRs, WebSockets. Another use is WebGL, it allows me to write simple multi-platform games in Go that target OS X, Linux, Windows, but also the browser. I would not be writing those games in JavaScript by a long shot.