The problem was in precedence of ternary operator and + sign.

Merge branch 'fix-nan'

+ Move ajax requests to promises base
+ Define constants for API URLs
+ Handle errors based on network connections problems as well as server-side logic errors
+ Generalize code so it can be used by modules & submodules simultaneously
+ Update name of module after 1 second, not waiting for focus out event

Just moved id attributes to data-id.
Don't think it was such a critical issue as I thought before.

+ Add animation for modules swaps
+ Add always / error callbacks to $.post requests
+ Remove usages of deprecated variables & functions
+ Format code, apply naming conventions

2. fix edit discipline

Добавление/Удаление бонуса