Redux best practice to filter data

Question

in the process of developing an application, I'm facing a question about whether I'm using Redux correctly. I have a fav:[] in which I add product objects and render their list. However, in order for the data not to be lost, I have to copy this fav:[] to favCopy:[] and only after that execute .filter Example code:

case "fav":
                state.fav = action.payload.filter === 'all'
                    ? state.favCopy
                    : state.favCopy.filter((item: any) => item[type] === action.payload.filter)

                break;

I would like to understand how right I am by keeping the original array intact? Maybe there is a way not to multiply arrays and use only one state?

Answer 1

We would recommend not doing filtering directly in the reducer most of the time. Instead, keep the original array in state as-is, and then also store a description of how you want the filtering to be done. From there, use selector functions to derive the filtered value as needed:

https://redux.js.org/usage/deriving-data-selectors