Just to point out - RxJs 5 allows you to bundle only operators you need, thus significantly lowering output file size. You could actually ship to the browser only features equivalent to those of this library. Not sure what actual numbers are though.
import "rxjs/add/operator/map"; import "rxjs/add/operator/reduce"; import "rxjs/add/operator/take"; import "rxjs/add/observable/of";
// etc. - this way you only get what you need into your bundle