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How does hoisting affect variables and functions?

Asked on Jun 26, 2025

Answer

Hoisting in JavaScript is a behavior where variable and function declarations are moved to the top of their containing scope during the compile phase, but not their initializations. This means you can use functions and variables before they are declared in the code.

<!-- BEGIN COPY / PASTE -->
        console.log(myVar); // undefined
        var myVar = 5;

        console.log(myFunction()); // "Hello, World!"
        function myFunction() {
            return "Hello, World!";
        }
        <!-- END COPY / PASTE -->

Additional Comment:

In the example, "myVar" is declared using "var", so it is hoisted to the top of its scope, but its initialization to "5" is not hoisted. Thus, "console.log(myVar);" outputs "undefined".
The function "myFunction" is fully hoisted, including its body, allowing it to be called before its declaration.
Variables declared with "let" and "const" are also hoisted but are not initialized, leading to a "Temporal Dead Zone" until the declaration is encountered.
Always declare variables and functions at the top of their scope to avoid confusion and potential errors.

✅ Answered with JavaScript best practices.

Ask any question about JavaScript here... and get an instant response.

How does hoisting affect variables and functions?

Asked on Jun 26, 2025

Answer

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