How to start setInterval loop immediately? [duplicate]

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);

Sometimes I use this pattern...

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

It's not quite the same, as it will wait until the do something is executed before waiting ~9 seconds to call it again. But, this is often useful so events on the event queue do not stack up needlessly (however unlikely it is some code will take 9 seconds to run :)

Note that in older IEs, the me will leak to the outside scope.

setInterval() is a really ugly function. I use this sanitized version, which does call the function immediately, and takes a time in seconds, BEFORE the function parameter so calling it with an inline function definition actually looks sensible.

function startInterval(seconds, callback) {  callback();  return setInterval(callback, seconds * 1000);}