No, this plugin works without Racer. I use it every day and I don't see any problems with code completion. Except of cases where code completion isn't supported

No, this plugin works without Racer. I use it every day and I don't see any problems with code completion. Except of cases where code completion isn't supported yet :) But it's all personal and better to try - it's free. To clarify: I'm not author of this plugin. And I tried Racer with Microsoft Visual Code plugin - it works without any lags, very fast. Just fails sometimes :)