Execute the setInterval function without delay the first time

Question

It's there a way to configure the setInterval method of javascript to execute the method immediately and then executes with the timer

Answer 1

It's simplest to just call the function yourself directly the first time:

foo(); setInterval(foo, delay); 

However there are good reasons to avoid setInterval - in particular in some circumstances a whole load of setInterval events can arrive immediately after each other without any delay. Another reason is that if you want to stop the loop you have to explicitly call clearInterval which means you have to remember the handle returned from the original setInterval call.

So an alternative method is to have foo trigger itself for subsequent calls using setTimeout instead:

function foo() {    // do stuff    // ...     // and schedule a repeat    setTimeout(foo, delay); }  // start the cycle foo(); 

This guarantees that there is at least an interval of delay between calls. It also makes it easier to cancel the loop if required - you just don't call setTimeout when your loop termination condition is reached.

Better yet, you can wrap that all up in an immediately invoked function expression which creates the function, which then calls itself again as above, and automatically starts the loop:

(function foo() {     ...     setTimeout(foo, delay); })(); 

which defines the function and starts the cycle all in one go.

Answer 2

I'm not sure if I'm understanding you correctly, but you could easily do something like this:

setInterval(function hello() {   console.log('world');   return hello; }(), 5000); 

There's obviously any number of ways of doing this, but that's the most concise way I can think of.