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What is the difference between let and var in JavaScript?

Asked on Mar 20, 2026

Answer

In JavaScript, "let" and "var" are both used to declare variables, but they differ in terms of scope and hoisting behavior. Here's a simple example to illustrate these differences:
// Example of 'var'
        function varExample() {
            if (true) {
                var x = 10;
            }
            console.log(x); // Outputs: 10
        }

        // Example of 'let'
        function letExample() {
            if (true) {
                let y = 20;
            }
            console.log(y); // ReferenceError: y is not defined
        }

        varExample();
        letExample();
Additional Comment:
  • "var" is function-scoped, meaning it is accessible within the function it is declared in, even if declared inside a block.
  • "let" is block-scoped, meaning it is only accessible within the block it is declared in.
  • "var" declarations are hoisted to the top of their function scope, while "let" declarations are hoisted to the top of their block scope but are not initialized.
  • Using "let" is generally preferred in modern JavaScript to avoid issues with variable hoisting and scope leakage.
✅ Answered with JavaScript best practices.
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