Call a function every N seconds using TypeScript

# Call a function every N seconds using TypeScript

Use the setInterval() method to call a function every N seconds in TypeScript.

The first parameter the method takes is the function that will be called on a timer and the second parameter is the delay in milliseconds.

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function logger(message: string) {
  console.log(`Logger got called with: ${message}`);
}

const seconds = 3;

// 👇️ call function every 3 seconds
setInterval(() => {
  logger('bobbyhadz.com');
}, seconds * 1000);

The 2 parameters we passed to the setInterval method are:

1. The function we want to invoke every delay milliseconds. Note that the first invocation happens after delay milliseconds (not instantly).
2. The time in milliseconds to delay between invocations of the function.

If I run the file from the code snippet above, I can see that the function is invoked every 3 seconds.

# Clearing the interval

The setInterval method returns an interval ID, which uniquely identifies the interval and can be used to cancel the interval.

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function logger(message: string) {
  console.log(`Logger got called with: ${message}`);
}

const seconds = 3;

const intervalID = setInterval(() => {
  logger('bobbyhadz.com');
}, seconds * 1000);

// 👇️ if some condition is met
// cancel the interval
clearInterval(intervalID);

You can use the clearInterval method to cancel the interval.

The only parameter the method takes is the unique identifier of the interval.

# Calling a function only once after N seconds

The setInterval method is used to call a function repeatedly. If you only need to call a function once after N seconds, use the setTimeout method instead.

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function logger(message: string) {
  console.log(`Logger got called with: ${message}`);
}

const seconds = 3;

setTimeout(() => {
  logger('bobbyhadz.com');
}, seconds * 1000);

We called the logger function a single time, after 3 seconds.

# Clearing the timeout

Similarly to setInterval, the setTimeout method returns a timeout ID, which you can use to cancel the timeout.

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function logger(message: string) {
  console.log(`Logger got called with: ${message}`);
}

const seconds = 3;

const timeoutID = setTimeout(() => {
  logger('bobbyhadz.com');
}, seconds * 1000);

// 👇️ if some condition is met
// cancel the timeout
clearTimeout(timeoutID);

The only parameter the clearTimeout method takes is the ID that uniquely identifies the timeout.

If you need to pass a function as a parameter, check out the following article.