Timer Module In Node

Node.js provides a built-in timer module, which is part of the events module. It includes functions for scheduling tasks, executing cron jobs, recurring tasks, and cancelling timer-based events.

The primary function for creating timers is setTimeout, and there's also setInterval for recurring events.

Here's a basic overview of the timer-related functions:

setTimeout(callback, delay):

Executes a callback function after a specified delay (in milliseconds). Optionally, we can pass additional arguments to the callback.

Example:

setTimeout(() => {
  console.log('Delayed function executed.');
}, 2000); // Execute after 2000 milliseconds (2 second)

Output:

Output:-> `Delayed function executed` will get print after 2 seconds delay.

setInterval(callback, delay):

Similar to `setTimeout`, but the callback function of `setInterval` is executed repeatedly at the specified interval. similarly, we have created a `setTimeout` function against `intervalId` to `clearInterval` after a specified period.

Example:

// stop interval after 5.1 second.
let countSecond = 0;

const intervalId = setInterval(() => {
  countSecond++;
  console.log(`Executed ${countSecond} times.`);
}, 1000); // Execute every 1000 milliseconds (1 second)

// To stop the interval after a certain time (e.g., after 5.1 seconds)
setTimeout(() => {
  clearInterval(intervalId);
  console.log('Stop Interval.');
}, 5100);

Output:

Executed 1 times.
Executed 2 times.
Executed 3 times.
Executed 4 times.
Executed 5 times.
Stop Interval.

clearInterval(intervalId) and clearTimeout(timeoutId):

Used to cancel a scheduled `timeout` or `interval`. Pass the timer ID returned by `setTimeout` or `setInterval` to clear it.

Example:

const timeoutId = setTimeout(() => {
  console.log('This will never be executed.');
}, 3000);

clearTimeout(timeoutId); // The timeout will be canceled, and the callback won't be executed.

const intervalId = setInterval(() => {
  console.log('This will never be executed.');
}, 1000);

clearInterval(intervalId);

Note: Both the timer will not print any Output because they were getting clear before move to browsers api.

process.nextTick(callback):

Schedules a callback function to be invoked in the next iteration of the event loop. It is not technically a timer, but it is often discussed in the context of timers.

Example:

process.nextTick(() => {
  console.log('it will get executed in next tick of the event loop.');
});

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