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JavaScript JavaScript Foundations Variables Shadowing

Surendra Kulkarni
Surendra Kulkarni
6,826 Points
Posted by Surendra Kulkarni
Surendra Kulkarni
6,826 Points

shadowing

In the code below: 

var person = "Jim";

function whosGotTheFunc() {
    person = "Andrew";
}

person = "Nick";

whosGotTheFunc();

console.log(person);

Ans: Andrew. My Q is outside of function var(global) person has be reassigned to "Nick" So the ans should be "Nick"?

2 Answers

Dino Paškvan
PLUS
Dino Paškvan
Courses Plus Student 44,108 Points
Dino Paškvan
Dino Paškvan
Courses Plus Student 44,108 Points

Yes, the global variable person has been reassigned to "Nick" but in the next line, it gets reassigned to "Andrew" by calling the whosGotTheFunct() function.

In this case, the function is not declaring a variable in its local scope (no var declaration), so instead, it's modifying the variable in the global scope.

The scopes are nested in JavaScript. Once the whosGotTheFunc() function is called, the JavaScript engine checks the scope to see if there is a local variable called person. Since there is no such local variable, it checks the scope that's one level above it (or just outside of this scope). In this case, this is the global scope. Global scope returns that there is a variable person declared in it, and the engine assigns the value "Andrew" to that variable.