reduce.ts

const reduce = (
  event: IEvent,
  state: typeof initialState
): typeof initialState => {
  if (event[0] === "change" && event[1] === "input-01") {
    const value = event[2];
    const filteredProducts = state.products
      .filter(({ name }) => name.toLowerCase().includes(value.toLowerCase()))
      .map(({ id }) => id);
    return {
      ...state,
      input: value,
      productsToDisplay: filteredProducts,
    };
  } else {
    return state;
  }
};