Use functional libraries to reduce code repetition and help do functional programming

[ArmandDu]

look into https://lodash.com/docs or https://underscorejs.org/

Pick one, read the doc and try to find where you could use some of the functions. for methods like map, filter, reduce, either use native ones or library's implementation

Hints: use chunk and map in your render method.

[trachanh1609]

Thanks ! Code refactored, also using lodash.