Immediately Executing setInterval with JavaScript

By  on  

Employing setInterval for condition polling has really been useful over the years. Whether polling on the client or server sides, being reactive to specific conditions helps to improve user experience. One task I recently needed to complete required that my setInterval immediately execute and then continue executing.

The conventional and best way to immediately call a function at the beginning of a setInterval is to actually call the function before the initial setInterval` is called:

myFunction();
setInterval(myFunction, 1000); // Every second

If you truly want to isolate the function call to the setInterval, you can use this trick of self-executing function that returns itself:

// Use a named function ...
setInterval(function myFunction() {
  // Do some stuff
  // ...

  // ... then return this function
  return myFunction;

// () self-executes the function
}(), 3000)

The down side to this pattern is that it causes a maintenance issue, where the next developer doesn't understand what is going on.

Maintenance is an important part of being a good engineer, so at the very least, documentation in the form of comments or a helper function should be required. If you really want to have a self-executing setInterval, you've got it!

Recent Features

Incredible Demos

  • By
    MooTools 1.3 Browser Object

    MooTools 1.3 was just released and one of the big additions is the Browser object.  The Browser object is very helpful in that not only do you get information about browser type and browser versions, you can gain information about the user's OS, browser plugins, and...

  • By
    Do / Undo Functionality with MooTools

    We all know that do/undo functionality is a God send for word processing apps. I've used those terms so often that I think of JavaScript actions in terms of "do" an "undo." I've put together a proof of concept Do/Undo class with MooTools. The MooTools...

Discussion

    Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!