How to display countdown timer in React - reactjs

Question

How can I show countdown timer in minute and seconds. right now I am able to show the timer in seconds, only but I want to display both minutes and seconds both.
Currently my countdown timer is showing in this way Countdown: 112 but I want it to be like Countdown: 1: 52
import React from "react";
export default function App() {
const [counter, setCounter] = React.useState(120);
React.useEffect(() => {
counter > 0 && setTimeout(() => setCounter(counter - 1), 1000);
}, [counter]);
return (
<div className="App">
<div>Countdown: {counter === 0 ? "Time over" : counter}</div>
</div>
);
}

Answer 1

Here's a complete solution with formatting time:
// Prepend `0` for one digit numbers. For that the number has to be
// converted to string, as numbers don't have length method
const padTime = time => {
return String(time).length === 1 ? `0${time}` : `${time}`;
};
const format = time => {
// Convert seconds into minutes and take the whole part
const minutes = Math.floor(time / 60);
// Get the seconds left after converting minutes
const seconds = time % 60;
//Return combined values as string in format mm:ss
return `${minutes}:${padTime(seconds)}`;
};
export default function App() {
const [counter, setCounter] = React.useState(120);
React.useEffect(() => {
let timer;
if (counter > 0) {
timer = setTimeout(() => setCounter(c => c - 1), 1000);
}
return () => {
if (timer) {
clearTimeout(timer);
}
};
}, [counter]);
return (
<div className="App">
{counter === 0 ? "Time over" : <div>Countdown: {format(counter)}</div>}
</div>
);
}
A few notes about your original code:
Since the next value of counter depends on the previous one it's better to use the functional form of setState.
It's a good practice to clear timeout when component unmounts.

Answer 2

Import hooks from import stage:
Hooks react
import React, { useState, useEffect } from "react";
export default function App() {
const [counter, setCounter] = useState(120);
useEffect(() => {
counter > 0 && setTimeout(() => setCounter(counter - 1), 1000);
}, [counter]);
return (
<div className="App">
<div>Countdown: {counter === 0 ? "Time over" : counter}</div>
</div>
);
}

Answer 3

Changing your setCounter method to following should work.
React.useEffect(() => {
counter !== 'Time Over' && setTimeout(() => setCounter(counter > 1 ? counter - 1 : 'Time Over'), 1000);
}, [counter]);

Answer 4

This can be done like so:
import React from "react";
export default function App() {
const [counter, setCounter] = React.useState(120);
React.useEffect(() => {
counter > 0 && setTimeout(() => setCounter(counter - 1), 1000);
}, [counter]);
return (
<div className="App">
<div>Countdown: {counter === 0 ? "Time over" : counter}</div>
</div>
);
}