Simple text timer in seconds written in React with Typescript

TextSecondTimer.test.tsx

import React from 'react';
import { render, act } from '@testing-library/react';
import TextSecondTimer from './TextSecondTimer';

describe('Text second timer component', () => {
  beforeEach(() => jest.useFakeTimers());

  it('shows zero if timeout is zero', () => {
    const { getByText } = render(<TextSecondTimer timeoutInSeconds={0} />);

    expect(getByText('0')).toBeVisible();
  });

  it('shows initial timeout value if timeout is below zero', () => {
    const { getByText } = render(<TextSecondTimer timeoutInSeconds={-5} />);

    expect(getByText('-5')).toBeVisible();
  });

  it('shows initial timeout value if timeout is greater than zero', () => {
    const { getByText } = render(<TextSecondTimer timeoutInSeconds={20} />);

    expect(getByText('20')).toBeVisible();
  });

  it('shows timeout value minus advanced time', () => {
    const { getByText } = render(<TextSecondTimer timeoutInSeconds={20} />);

    act(() => {
      jest.advanceTimersByTime(10000);
    });

    expect(getByText('10')).toBeVisible();

    act(() => {
      jest.advanceTimersByTime(10000);
    });

    expect(getByText('0')).toBeVisible();
  });

  it('shows zero after all timers have run', () => {
    const { getByText } = render(<TextSecondTimer timeoutInSeconds={20} />);

    act(() => {
      jest.runAllTimers();
    });

    expect(getByText('0')).toBeVisible();
  });
});

TextSecondTimer.tsx

import React, { useEffect, useState } from 'react';

interface Props {
  timeoutInSeconds: number;
}

export default function TextSecondTimer({ timeoutInSeconds }: Props) {
  const [timeLeftInSeconds, setTimeLeftInSeconds] = useState<number>(timeoutInSeconds);

  useEffect(() => {
    setTimeLeftInSeconds(timeoutInSeconds);
  }, [timeoutInSeconds]);
  
  useEffect(() => {
    const interval: number = setInterval(() => {
      const newTimeLeftInMillis = timeLeftInSeconds - 1;
      return newTimeLeftInMillis < 0
        ? clearInterval(interval)
        : setTimeLeftInSeconds(timeLeftInSeconds - 1);
    }, 1000);
    return () => clearInterval(interval);
  });

  return (<>{ timeLeftInSeconds }</>);
}