Will JavaScript Closure save all variables in its scope, or only those the closure referred?

Question

We knew that

function foo () {
  var x = 10;
  var y = 20;
  function bar () {
    return x + 1;
  }
  bar(); // 11
}

The function bar create a closure, and save the reference of x.

But what about the variable y? Will the closure bar created hold its reference? I tried it in Chrome Dev Tools, and it shows only x in the [[Scopes]] field, without y. But I can not find any articles about that.

Does it means the closure creation will only pick what it need to save?

Are you asking about what should happen according to the specification or how different engines implement closures? — Felix Kling, Apr 20 '17 at 03:25
http://stackoverflow.com/questions/32325223/over-how-much-of-its-enclosing-scope-does-a-javascript-closure-close — nnnnnn, Apr 20 '17 at 03:25
Note that in the code shown there is no reference to `bar()` outside of `foo()`, so the closure concept isn't really relevant. — nnnnnn, Apr 20 '17 at 03:35

score 0 · Answer 1 · edited May 23 '17 at 12:25

0

Scopes are chained together and it'll check with parent scope when reference cannot be find. This question is answered before and you can reference it here: Scope Chain in Javascript

edited May 23 '17 at 12:25

Community

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answered Apr 20 '17 at 03:36

Brilly Tsang

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Will JavaScript Closure save all variables in its scope, or only those the closure referred?

1 Answers1