TypeScript - setInterval() function example

In this article, we would like to show you how to use setInterval() in TypeScript.

Quick solution:

setInterval((): void => {
  console.log('This will be displayed every 1000ms (1s).');
}, 1000);

or:

const handle = setInterval((): void => {
  console.log('This will be displayed every 1000ms (1s).');
}, 1000);

clearInterval(handle); // stops intervals

1. Documentation

Below we present some practical examples for better understanding.

1. Simple setInterval example

In this example, we create and call a simple function that displays some text every second.

Runnable example:

setInterval((): void => {
  console.log('This will be displayed every 1000ms (1s).');
}, 1000);

2. Calling setInterval the specified amount of times

In this example, we create a function with setInterval that counts to 5 every second.

Runnable example:

let i = 0;
const interval = setInterval((): void => {
  console.log(i + 1);
  if (++i === 5) {
    clearInterval(interval);
  }
}, 1000);

3. Custom setInterval

In this example, we create customSetInterval that takes in three arguments:

• count - how many times we want to call the callback function,
• delay - time between callback function calls,
• callback - a function to be called.

Runnable example:

const customSetInterval = (count: number, delay: number, callback: (i: number, count: number) => void): void => {
  let i = 0;
  const interval = setInterval(() => {
    callback(i, count);
    if (++i === count) {
      clearInterval(interval);
    }
  }, delay);
};

// Usage example:

const foo = (index: number, count: number): void => console.log(`${index + 1}/${count} Some text here ...`);

customSetInterval(5, 1000, foo);

Output (one line every second):

1/5 Some text here ...
2/5 Some text here ...
3/5 Some text here ...
4/5 Some text here ...
5/5 Some text here ...