Play with this app at https://avu120.github.io/countdown-timer/.
User can write the name of a future event then select the date and time it will start. A timer will then display the total time until that event starts and count down by 1 second intervals in real time. When the timer hits 0, an event notification will occur. User will then be prompted to change event name, select a new date and time and start the countdown again. Timer can be reset while running.
Run application at: https://avu120.github.io/countdown-timer/
View/edit/fork CodeSandbox at: https://codesandbox.io/s/github/AVu120/countdown-timer
git clone https://github.com/AVu120/countdown-timer.git
cd countdown-timer
npm i
npm start
Then open http://localhost:3000 in a browser.