Javascript closures with two instantiation -

i trying understand closure, , playing following code.i expecting value of same across objects,as closure keeps reference variable of outer function.

 function test(){  var i=10;  return{    get:function(){return i;},    inc:function(){i++;}    }  } var test1= test(); var test2=test(); test1.get(); //outputs 10 test1.inc(); test2.get(); //outputs 10, expecting 11 

is understanding of closures correct, creating closure in case? new closures, detailed explanation great. thanks.

as others have mentioned, you've created 2 closures.

the easiest way understand closures is generalisation of concept of global variables. in fact, global variables in javascript nothing more closure in global scope.

a closure mechanism body of function may reference variables in outer scope. said above, global variables nothing more closure:

var x;  function x_plus_plus () {     x++; // variable captured closure } 

every scope allows create closure. apart global scope can create closure inside other functions. me, personally, minimum example code best illustrates closures iife defines 2 functions share variable:

var incr; var val;  (function(){     var x = 0; // shared functions below var via closure      incr = function(){x++};     val = function(){return x}; })();  incr(); incr(); console.log(val()); // outputs 2 because functions share x  console.log(x); // syntax error - x not exist in scope 

note closure happens between variable , functions declared in variable's scope. not happens between variable , function variable declare in:

function () {  <─────┐                      ├── not closure     var foo; <───────┘ }  function () {     var foo;   <────────────────┐                                 ├── closure     function bar () {           │         do_something(foo);  <───┘     } }  var x;   <───────────────┐                          ├── closure function y () {          │   call "global variable"      do_something(x); <───┘ } 

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side note: global variables in js bit unique because they're properties of global (window) object. in theory behave if they're instance of closure. point thinking of closures global-variable-like mechanism easiest way understand them.