my biggest interest in server side js is what i call offloading<p>i have server side code that can do a lot of heavy data calculations, and i client side code that can do a lot of heavy presentation calculations, and then i have the internet as a connection between them<p>since the presentation layer is burdened by needing to be sent to the client over the connection i have a constant optimisation interest in the size of the client code<p>if i am concerned about the time and data cost on the client, i can do a lot of presentation calculations on the server and send the results stead the source that found them<p>alternatively, if i am unconcerned with the time and data cost on the client, i can send more server code to the client to offload some of the work to relieve the server<p>because of this constant optimisation interest i always duplicate my server functions, whatever language they may be, in the presentation source.. currently javascript.. and vice versa<p>so i can decide on the fly where any function will run when situations define the optimal configuration<p>server side js would limit the extra work in some cases<p>but i doubt i&#x27;d utilise it because i find the transliterating step to be valuable in hardening the code and logic underlying