How to start setInterval loop immediately? [duplicate]

Question

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);