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What is the !! (not not) operator in JavaScript?
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Converts Object to boolean. If it was falsey (e.g. 0, null, undefined, etc.), it will be false, otherwise, true.
!oObject // inverted boolean
!!oObject // non inverted boolean so true boolean representation
So !! is not an operator, it's just the ! ...
How do you properly use namespaces in C++?
...e object into packages, and then reusing them later from that package. But now I'm working in C++.
15 Answers
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Difference between freeze and seal
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FWIW, frozen and sealed objects are now faster than their unfrozen and unsealed counterparts in Chrome Canary v43.0.2317.0.
– llambda
Feb 28 '15 at 22:57
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What is the difference between a shim and a polyfill?
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Shim
If you are familiar with the adapter pattern, then you know what a shim is. Shims intercepts API calls and creates an abstract layer between the caller and the target. Typically shims are used for backward compability. For instance the es5-shim npm package will let you write ECMAS...
LESS CSS nesting classes
...s1 {
.class2 {}
}
defines nested nodes. .class2 will only be applied if it is a child of a node with the class class1.
I've been confused with this too and my conclusion is that LESS needs a this keyword :).
share
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How does `is_base_of` work?
...tness anymore. In an ordinary overload resolution scenario, the call would now be ambiguous because normally the return type won't participate in overload resolution. For conversion functions, however, there is a backdoor. If two conversion functions are equally good, then the return type of them de...
I lost my .keystore file?
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Now it is possible don't worry, here is the full and final steps to reset .JKS file.
Step-1
Download the UPLOAD CERTIFICATE (file name - upload_cert.der) from your Google Play Store Console
Step-2
Go to this LINK http...
How to make a in Bootstrap look like a normal link in nav-tabs?
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Shows differently than links.
– Ciro Santilli 郝海东冠状病六四事件法轮功
Oct 5 '14 at 9:35
1
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Android image caching
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And now the punchline: use the system cache.
URL url = new URL(strUrl);
URLConnection connection = url.openConnection();
connection.setUseCaches(true);
Object response = connection.getContent();
if (response instanceof Bitmap) {...
Best way to create unique token in Rails?
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-- Update --
As of January 9th, 2015. the solution is now implemented in Rails 5 ActiveRecord's secure token implementation.
-- Rails 4 & 3 --
Just for future reference, creating safe random token and ensuring it's uniqueness for the model (when using Ruby 1.9 and ActiveR...