why use the "!!!"?

Posted by lazyanno on Stack Overflow See other posts from Stack Overflow or by lazyanno
Published on 2010-06-11T04:15:42Z Indexed on 2010/06/11 4:22 UTC
Read the original article Hit count: 172

Filed under:

JavaScript

|

Performance

|

data-structures

as follow codes:

var a = {};
if(!!!a[tabType]){
   a[tabType] = [];
   a[tabType].push([self,boxObj]);
}else{
   a[tabType].push([self,boxObj]);
}

i think !!!a[tabType] equals !a[tabType] why use the "!!!" not "!" ?

thank you!

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