Immediately Executing Functions
JavaScript is full of nifty little tricks to accomplish tasks with less code. One of those tricks is immediately executing functions. We oftentimes see this pattern for executing anonymous functions to limit variable scope:
(function() {
console.log('executed!');
// Do processing here
})();
What many developers don't know is that this code can be shorted by using a ! before the anonymous function:
!function() {
console.log('executed!');
// Do processing here
}()
The function above executes immediately, just as the first snippet did. One caveat: the immediately executing function always returns false. If you desire the result of the anonymous function, you wont want to use this second pattern.
Ben Alman has created an excellent, detailed writeup on the subject and if you want to learn more, be sure to visit his post!
![An Interview with Eric Meyer]()
Your early CSS books were instrumental in pushing my love for front end technologies. What was it about CSS that you fell in love with and drove you to write about it?
At first blush, it was the simplicity of it as compared to the table-and-spacer...
![Create Namespaced Classes with MooTools]()
MooTools has always gotten a bit of grief for not inherently using and standardizing namespaced-based JavaScript classes like the Dojo Toolkit does. Many developers create their classes as globals which is generally frowned up. I mostly disagree with that stance, but each to their own. In any event...
![JavaScript Copy to Clipboard with Branding]()
I published a post a year ago detailing how you can copy to the clipboard using JavaScript. The post was very popular and why would it be? Copying content from a webpage without needing to use the default browser functions is awesome. One trend I've...
![CSS Background Animations]()
Background animations are an awesome touch when used correctly. In the past, I used MooTools to animate a background position. Luckily these days CSS animations are widely supported enough to rely on them to take over JavaScript-based animation tasks. The following simple CSS snippet animates...
Because not quite enough people pulled out their hair on encountering the function(){…}() syntax.
The first is not exactly valid. The right call has the call-parentheses inside the container parentheses.
(function() { ... code ... }())I think the ! is works with call-parentheses too. So it’s not shorter.
> !function(){console.log('asd')} false > !function(){console.log('asd')}() asd true > function(){console.log('asd')}() asd undefined > (function(){console.log('asd')}()) asd undefined >I think such oddities should be removed from the language.
What would ever be the argument for doing this? A Obfuscated Javascript Code Contest?
Why even use such a function? I don’t get it. If you want code to execute immediatly, just write it outside a ‘function’. What’s the point of an anonymous function you can’t call later on for reusability? Or am I missing something?
Encapsulation of vars…