bluePhaseUpdate.ts

const filterProducts = (event: IEvent, state: IState) => {
  const value = event[2] || "";
  const filteredProducts = state.products
    .filter(({ name }) => name.toLowerCase().includes(value.toLowerCase()))
    .map(({ id }) => id);
  return {
    ...state,
    input: value,
    productsToDisplay: filteredProducts
  };
};

export const update = (event: IEvent, state: IState) => {
  const isInputUpdated =
    event[0] === "change" &&
    event[1] === "input-01" &&
    filterProducts(event, state);
  return isInputUpdated || state;
};