Question

I am using the setInterval() function to call a function every 20 seconds. However, one thing I noticed is that it the first time setInterval() actually calls the function is at 20 seconds (and not when setInterval() is called). Here is my current workaround:

dothis();
var i = setInterval(dothis, 20000);

Is there any way to achieve this without having this duplicate code?

Answer 1

Your method is THE normal way way of doing it.

If this comes up over and over, you could make a utility function that would execute the handler first and then set the interval:

function setIntervalAndExecute(fn, t) {
    fn();
    return(setInterval(fn, t));
}

Then, in your code, you could just do this:

var i = setIntervalAndExecute(dothis, 20000);