How does this structure work when the function is anonymous?
!function() {
.
.
.
}();
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returned value NOT ed, `!false` – Grijesh Chauhan Jan 27 '14 at 12:56
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3Also see http://stackoverflow.com/questions/9091289/javascript-anonymous-function-call, which, in turn, seems to be a triple duplicate. ) – raina77ow Jan 27 '14 at 12:57
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The anonymous function is executed, but the return value is not used anywhere. – Teemu Jan 27 '14 at 13:03
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There's no test for existence. The return value is negated and discarded. – John Dvorak Jan 27 '14 at 13:37
2 Answers
2
With a return value.. you negate that with !
var x=!function(){return false}();
console.log(x);
// true
double negation
var pizza='pizza';
var x=!!function(){return pizza}();
console.log(x);
// true
// returns true if pizza is defined, not 'pizza'
// returns false if pizza is ''.
demo
cocco
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Pretty much as with any other thing. The anonymous function is autoexecuted, therefore returns a value, and the value is negated.
bgusach
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