Patterns for deriving state gist7

code.js

function sortingReducer(state,action){
  switch (action.type){
    case actionTypes.SORT_BY:
      const key = action.payload;
      return {
        list:state.list.sort((a,b)=>a[key]>b[key]?1:a[key]<b[key]?-1:0),
        sortKey:key
      }     
      default:
        return state;
  } 
}