const reduxState = {
  bookByName: {},
};

const selectBooks1 = proxyMemoize.memoize((state) => Object.values(state.bookByName));

let prevBookByName;
let prevBooks = [];

const selectBooks2 = (state) => {
  if (state.bookByName !== prevBookByName) {
    prevBookByName = state.bookByName;
    prevBooks = Object.values(prevBookByName);
  }

  return prevBooks;
};