How to start setInterval loop immediately? [duplicate]

Question

In a simple setInterval

setInterval(function() {       // Do something every 9 seconds }, 9000); 

The first action will happen after 9 seconds (t=9s). How to force the loop to perform the first action immediately (t=0)?

I think it is due to the mechanism of setInterval to have Delay - Action - Delay - Action ... loop; instead of Action - Delay - Action - Delay ... loop.

EDIT: My function is indeed a loop as

setInterval(function(){ $('.test').each(function(idx){     var duration = 1000;     $(this).delay(duration*idx);     Some stuff here }); }, 4000); 

Answer 1

Keep it simple. You can use a named function instead of an anonymous function; call it and set an interval for it.

function doSomething() {     console.log("tick"); } doSomething(); setInterval(doSomething, 9000); 

Create a scope if necessary:

(function() {     function doSomething() {         console.log("tick");     }     doSomething();     setInterval(doSomething, 9000); })(); 

Finally, the following works without creating or affecting x:

setInterval(function x() {     console.log("tick");     return x; }(), 9000);