Timeouts & Intervals

setinterval()

• The setinterval() function repeatedly runs the same code over and over again at regular intervals.

setInterval(function, duration, param1, param2, ...);

• The first parameter is the code to execute.

• *The second parameter is the duration in milliseconds.

• After the second parameter, you can pass in zero or more values that represent any parameters you want to pass to the function when it is run.

function greet() {
  console.log("Hello");
}

setInterval(greet, 20090)
// -> Logs ‘Hello’ every 2 seconds

clearInterval()

• Intervals keep running a task forever so you should clear the interval when appropriate.

const intervalId = setInterval(greet, 2000, 'Vishwas');
clearInterval(intervalId);

setInterval & setTimeOut: Noteworthy points

• It is possible to achieve the same effect as setinterval with a recursive setTimeout.

setTimeout(function run() {
  console.log('Hello')
  setTimeout(run, 100);
}, 100);
// output 'Hello' to endless loop each 100ms

1. Duration is guaranteed between executions:

2. Irrespective of how long the code takes to run, the interval will remain the same.

3. Code can take longer to run the the time interval itself? Recursive setTimeout.

4. You can calculate a different delay before running each iteration.

setInterval( () => {
  console.log( ‘Hello’ )
}, 100);

1. The duration interval includes the time taken to execute the code you want to run:

2. The code takes 40ms to run, the interval is 60ms

3. The code takes 50ms to run, the interval is 50ms

4. setinterval is always a fixed interval duration