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Consider the following JavaScript code:
function outer() {
  var x = 10;
  function inner() {
    console.log(x);
  }
  return inner;
}
var closureFn = outer();
closureFn();
What will be the output of the above code?
  • a)
    10
  • b)
    0
  • c)
    Undefined
  • d)
    This code will produce an error
Correct answer is option 'A'. Can you explain this answer?
Most Upvoted Answer
Consider the following JavaScript code:function outer() { var x = 10; ...
Explanation:
- The code snippet provided defines a function called `outer()` that contains a variable `x` with a value of 10.
- Inside the `outer()` function, there is another function called `inner()` that simply logs the value of `x` to the console.
- The `inner()` function is then returned from the `outer()` function.
- The line `var closureFn = outer();` invokes the `outer()` function and assigns the returned `inner()` function to the variable `closureFn`.
- Finally, the line `closureFn();` calls the `inner()` function stored in the `closureFn` variable.

Output:
The output of the code will be `10`.

Explanation:
- When the `inner()` function is returned from the `outer()` function, it forms a closure.
- A closure is a combination of a function and the lexical environment within which that function was declared.
- In this case, the `inner()` function has access to the variable `x` from its parent function `outer()`, even after the `outer()` function has finished executing.
- When the `closureFn()` function is called, it executes the `inner()` function and logs the value of `x` to the console, which is `10`.
- This is because the `inner()` function maintains a reference to its outer environment, including the variable `x`.
- Therefore, the value of `x` is accessible to the `inner()` function even though it is no longer in scope.
- This behavior is characteristic of closures in JavaScript, where functions retain access to variables from their containing scope even after the outer function has completed execution.
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Community Answer
Consider the following JavaScript code:function outer() { var x = 10; ...
The code defines a function named "outer" that declares a variable "x" with the value 10. Inside "outer", there is a nested function named "inner" that logs the value of "x" to the console. Finally, the "inner" function is returned from "outer" and assigned to the variable "closureFn". Calling "closureFn()" executes the "inner" function, which accesses the value of "x" from its outer scope. Therefore, the output is 10.
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