Patterns for deriving state gist6

code.js

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