Using a SVN or GIT as version control system is very useful, but when several developers are working within a same Sprint on the same bunch of source files, it can rapidly become messy and lead to endless resolutions of merge-conflicts.
Instead of splitting development into functions or methods, think of code interaction by allowing controllers to call each other can be very helpful
Instead of calling a method, a script / controller can request the result from (or invoke action to) another controller.
As controllers are described within distinct files, this practice decreases the risk of conflict when code is updated.
This practice applies to most frameworks, both front-end and back-end: