Modernizr javascript code explanation

Question

I'm working on some HTML5 template and I'm watching some examples on the internet how other guys done it , since I would like to put my work on Theme Forest , I found this peace of code in one of examples and I really cant get it how it works . So please if anyone could help me to understand this it would be great

var pd = {},
verboseBuild = !0,
screenXs = 480,
ltIE9 = !1;

/* Modernizer */

!$("html").is(".lt-ie9") || (ltIE9 = !0),

Modernizr.addTest("ipad", function () {
    return !!navigator.userAgent.match(/iPad/i);
}),
Modernizr.addTest("iphone", function () {
    return !!navigator.userAgent.match(/iPhone/i);
}),
Modernizr.addTest("ipod", function () {
    return !!navigator.userAgent.match(/iPod/i);
}),
Modernizr.addTest("appleios", function () {
    return Modernizr.ipad || Modernizr.ipod || Modernizr.iphone;
}),
Modernizr.appleios && $("html").addClass("ios-device"),
    !verboseBuild || console.log("Starting builds:"),
    $(document).ready(function () {
        !verboseBuild || console.log("-- starting proton.common build"), 
        pd.common.build();
    }),

and can anyone explain what verbosebuild = !0 mean and itE9 = !1 too?

Thanks !

Edgar Villegas Alvarado · Accepted Answer · 2014-01-12 01:03:51Z

1

Well:

!0 is just an alias for true
!1 is just an alias for false
!!<something> in simple words, casts <something> to boolean (will always return true or false)

(Btw, I don't know the reasons why their developers did the first 2, In my opinion, that would be microoptimization, that shouldn't be done).

So, for example:

ltIE9 = !1 means IE version is 9 or higher

Hope this helps. Cheers

edited Jan 12, 2014 at 1:03

answered Jan 12, 2014 at 0:44

Edgar Villegas Alvarado

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3 Comments

Adam Jenkins Over a year ago

Just curious, how is !1 a microoptimization? Doesn't JS have to evaluate 1 to true first? I would've that that false would've been faster than !1

Edgar Villegas Alvarado Over a year ago

I'm not sure if it is, but I couldn't think of other reason they did it. Why do you think they did it?

Adam Jenkins Over a year ago

Misguided ego, is my opinion. Seasoned developers will know the developer who wrote this is just blowing hot air, novice developers will be "impressed" (unfortunately) by the abstract and unusual syntax and think that the developer that wrote this must know something that they don't. Ultimately, !0 and !1 is absolutely nonsense.

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