Refactoring of client-side code

[mwittep]

Description

To improve the quality of the code, as mentioned in some reviews, developers should revise some code aspects and try to refactor. Especially, if a code looks copy-pasted, try to abstract it. Moreover, be consistent of function naming or even extract them to a common file that can be included across many components.

Important: Please, create a new branch and do not push until the feature has been tested by yourself!

Acceptance

• The developers of the client-side take available reviews into account and improve the code of the front-end.