What Is Lexical Scope in JavaScript?

What Is Lexical Scope in JavaScript?

Lexical scope determines how variables are accessed in JavaScript.

The word "lexical" means that scope is determined by where code is written.

Example

function outer() {
  let name = "John";

  function inner() {
    console.log(name);
  }

  inner();
}

The inner function can access variables declared in its outer scope.

How Lexical Scope Works

JavaScript determines variable accessibility based on the physical placement of functions in source code.

Functions can access:

• Their Own Variables
• Parent Scope Variables
• Global Variables

Why Is Lexical Scope Important?

Lexical scope forms the foundation for:

• Closures
• Scope Chains
• Data Encapsulation
• Modular Code

Without lexical scope, closures would not exist.

Common Interview Topic

Interviewers frequently ask lexical scope questions because they test a candidate's understanding of JavaScript internals.

The Bottom Line

Lexical scope means variable access is determined by where functions are defined in the source code, not where they are executed.