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setInterval run once, then keep running
setInterval((function () {
console.log(new Date()); // run some arbitrary code
return arguments.callee; // here be the magic
})(), 1000);
// ^---- and that runs the function, and the return val is assign to the interval
@jonraasch

Awesome, I've always wondered if that was possible.

@paulirish

an ecmascript5 strict mode safe version, without arguments.callee:

setInterval((function fn() {
    console.log(new Date()); // run some arbitrary code
    return fn;               // here be the magic
})(), 1000);
// ^---- and that runs the function, and the return val is assign to the interval
@remy
Owner
remy commented Apr 8, 2010

Yeah, it should be noted that, as per Paul's comment - es5 doesn't support arguements.callee - in fact, I think Paul's is cleaner code since you've got a named function to help with debugging and performance.

@cowboy
cowboy commented Apr 8, 2010

I have a gist fork of this one with some setInterval and setTimeout patterns in it.

@getify
getify commented Apr 8, 2010

isn't this going to create memory leaks in IE with the named function expression?

@rakeshpai

How does a named function help with performance?

Also, I prefer the arguments approach better, since it's very useful when creating, say, a library. If I pass the arguments object to the library, the lib has got context of both caller and callee with a simple API. In ES5, the API would get complicated. This has been my biggest gripe with ES5.

@paulirish

Accessing the arguments object is very slow.
http://www.jspatterns.com/arguments-considered-harmful/
http://webreflection.blogspot.com/2010/02/arguments-callee-call-and-apply.html

@getify, i'm aware of the NFE scope leaking bugs in IE, but not any memory leaks..

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