javascript - Json data formatting best practice -

i have spa web page. data loaded ajax requests. need show culture sensitive data on page. best way formating kind of data? basicaly have 2 options:

1. send data preformated client (preformat on server)

preformated {     durrationinminutes = '2 min'     durationinseconds = '120 sec' } 

pros:

• easy server side implementation (asp.net mvc back-end).
• everything in 1 place (one method in bll).
• smaller javascript

cons:

• posible data duplication (same duration data shown in minutes, seconds i.e. diferent format same data).

2. send raw data client (format on client)

rawdata {         durration = 1645678 // milliseconds         } 

pros:

• easier unit testing (we can test in c#)
• easier maintenance - our developers more expirienced in c# then
  javascript

cons:

• more work has done on client side
• i'm not sure if data formating can easilly done in javascript

edit

i end client side option

thanks

for simple presentation of data, both methods ok. keep in mind couple of other considerations:

• all data sent client in principle available user, if it's not shown directly. can in situations security issue.
• sending raw data client , letting client handle rest gives more possibilities dynamic viewing on client side
• depending on type of application , data, sending data client can reduce load on server. users slow clients can issue.

if none of these considerations apply, go optimal developing , maintenance. answer depends on local issues, resources, framework used etc.