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Javascript Closure

/ Published in: JavaScript
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Apologies if I haven't explained this to well, I'm still trying to get my head round closures.

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  1. /*
  2.  * Since we are passing the inner function outside, a reference to it
  3.  * still exists, hence it is not collected by the garbage collector.
  4.  * 
  5.  * The variable a persists through to the next increment, and is not overwritten
  6.  * by outer() var a = 0 since inner still has a local variable inside it's scope.
  7.  * 
  8.  * By creating global2, you have created another scope that acts independently,
  9.  * even though they are using the same function literal! 
  10.  */
  11. function outer(){//define outer scope
  12. 	var a = 0;//this is the persistent variable
  13. 	function inner(){//define the inner scope
  14. 		a++;//increment a
  15. 		console.log(a);
  16. 	}
  17. 	return inner;//IMPORTANT: return the inner function to the outside (scope)
  18. }
  19. var global = outer();//create a new scope in global
  20. global();//a = 1
  21. global();//a = 2
  22. var global2 = outer();
  23. global2();//a = 1
  24. global2();//a = 2

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