Check LocaleStorage via Unit tests in React

Question

I have been trying to mock my localeStorage with that library https://www.npmjs.com/package/jest-localstorage-mock But it always shows me the next mistake

SyntaxError: Unexpected token u in JSON at position 0 at JSON.parse ()

Here is mine test

    it('checks the locale cost element', () => {
  const headerCoinCost = 544123.123543;

  const KEY = "walletData",
    VALUE = '[{"id":"bitcoin","name":"Bitcoin","price":"38953.6908005677844877","amount":"1"}]';

  render(<HeaderWallet headerCoinCost={headerCoinCost} onClick={true ? true : false} ></HeaderWallet>);

  const userWalletDifferenceElement = screen.getByTestId("user-wallet__different-cost-test");
  expect(userWalletDifferenceElement).toBeInTheDocument();

  dispatch(action.update(KEY, VALUE));
  expect(localStorage.setItem).toHaveBeenLastCalledWith(KEY, VALUE);
  expect(localStorage.__STORE__[KEY]).toBe(VALUE);
  expect(Object.keys(localStorage.__STORE__).length).toBe(1);

  expect(userWalletDifferenceElement).toHaveTextContent(544123.12);
});

component where I get mistake

    export const getLocaleCost = () => {
  let localCostArr = [];
  let sum = 0;

  let existingEntries = JSON.parse(localStorage.getItem("walletData"));
  if (existingEntries == null) existingEntries = [];

  existingEntries.map(el => {
    localCostArr.push(el.price * el.amount)
  });

  for (let i = 0; i < localCostArr.length; i++) {
    sum += +localCostArr[i];
  };

  return sum;
};