node.js: how to use setInterval and clearInterval?

user_300675 0
Viewed 98791

This is my JS in nodeJS :

function test(a, room, seconds) {
    console.log(a, room, seconds);
}

intervalid = setInterval(test, 1000, 'room', 20);
console.log('intervalid', intervalid);

Which returns me the output: 

intervalid Timeout {
    _called: false,
    _idleTimeout: 1000,
    _idlePrev: TimersList {
        _idleNext: [Circular],
        _idlePrev: [Circular],
        _timer: Timer { '0': [Function: listOnTimeout], _list: [Circular] },
        _unrefed: false,
        msecs: 1000,
        nextTick: false
    },
    _idleNext: TimersList {
        _idleNext: [Circular],
        _idlePrev: [Circular],
        _timer: Timer { '0': [Function: listOnTimeout], _list: [Circular] },
        _unrefed: false,
        msecs: 1000,
        nextTick: false
    },
    _idleStart: 377,
    _onTimeout: [Function: test],
    _timerArgs: [ 'room', 20 ],
    _repeat: 1000
}

Whereas in simple Javascript it returns a simple INTEGER number

When I attach interval to an existing user object, example :

user.intervalid = setInterval(test, 1000, 'room', 20);

I am not able to clearInterval any more :

clearInterval(user.intervalid); // does not work
node.js
5 Answers

Using setInterval()

What if you need to repeat the execution of your code block at specified intervals? For this, Node has methods called setInterval() and clearInterval(). The setInterval() function is very much like setTimeout(), using the same parameters such as the callback function, delay, and any optional arguments for passing to the callback function.

A simple example of setInterval() appears below:

var interval = setInterval(function(str1, str2) {
  console.log(str1 + " " + str2);
}, 1000, "Hello.", "How are you?");

clearInterval(interval);

This is another way when you want to keep only one interval running every minute 

function intervalFunc() {
    console.log("Hello!!!!");
     }
    setInterval(intervalFunc,1500);

In the above example, intervalFunc() will execute about every 1500 milliseconds, or 1.5 seconds, until it is stopped . Hope this helps.

user_76358450

If you want a JavaScript like interval ID after creating a setInterval timer, you can do the following,

function callbackFunc() {
  console.log("I'm just an example callback function");
}

const timeoutObj = setInterval(callbackFunc, 1000);
const intervalId = timeoutObj[Symbol.toPrimitive](); //intervalId is an interger

// Later you can clear the timer by calling clearInterval with the intervalId like,
clearInterval(intervalId);

Note: This only works when your node version is >= v12.19.0.

user_36071910

This just caught me. Exactly the same scenario, clearInterval simply wasn't working.

Looking in the console, the result of setInterval was an object, not a number. I was quite confused.

The solution was to remove this import statement, which had snuck in:

import { setInterval } from 'timers';

user_20323840

setInterval() takes a function argument that will run an infinite number of times with a given millisecond delay as the second argument.

setInterval(()=> {
  console.log('Every 1 second');
},1000)
console.log('I will run first');

How to use clearInterval():

var xyz = setInterval(()=> {
  console.log('Every 1 second');
},1000)
console.log('I will run first');

clearInterval(xyz);
user_137493830
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