JavaScript: how are functions and their scopes/lexical environments passed around? -

i'm playing closure , have no problem understanding how inner functions have access outer lexical environments:

function outer() {   var bar = 0;   function inner() {     console.log(bar);   }   inner(); } outer();    // prints '0' 

but gets me this:

function foo() {   return function inner() {     console.log(bar);   } } function outer() {   var bar = 0;   var fakeinner= foo();    // not same "var fakeinner= function () { console.log(bar); }"   fakeinner(); } outer();    // referenceerror: bar not defined 

here try "define" "inner function" fakeinner assigning function expression returned outside function.

i used think javascript creates fakeinner inside "copy" of code, like: var fakeinner= function () { console.log(bar); }, have access bar, not case -- appears when fakeinner invoked, javascript traces definition. understanding correctly? is, function objects (either declarations or expressions) mere references definition spots, , passing them not change lexical environments (hence inner functions have defined inside explicit syntax)?

yes, functions have access own lexical environment - defined. javascript not have dynamic scope function has kind of access scope called.

this happens attaching scope function object, part of closure.