Modern Web Design with HTML5, CSS3, and JavaScript - JavaScript Function Closures with Examples

The video tutorial delves into the concept of closures in JavaScript, highlighting their power and utility. It explains how closures allow functions to access variables from their parent scope, even after the parent function has executed. The tutorial provides two examples: one involving a secret formula and another using a secret name, to demonstrate how closures work in practice. It concludes with a recommendation to explore further resources on the Mozilla Developer Network for a deeper understanding.

What is a closure in JavaScript?

• A function that can access variables from its own scope only.

• A function that can access variables from its own scope and the global scope.

• A function that can access variables from its own scope and the parent scope.

• A function that cannot access any variables outside its own scope.

In the secret formula example, what is the purpose of returning a function?

• To make the function run faster.

• To prevent the function from accessing any variables.

• To allow the function to be reused later.

• To immediately execute the function.

Why is it necessary to assign the returned function to a variable?

• To make the function run in a different scope.

• To prevent the function from being garbage collected.

• To ensure the function can be invoked later.

• To modify the function's behavior.

In the second example, what does the closure allow the function to do?

• Access variables from its parent scope even after the parent function has finished executing.

• Access and modify variables from its own scope only.

• Prevent any access to variables from the parent scope.

• Access variables only from the global scope.

What is the significance of using closures in JavaScript?

• They make functions run faster.

• They allow functions to be executed only once.

• They enable functions to remember the environment in which they were created.

• They prevent functions from accessing any variables.

How can closures be beneficial in JavaScript programming?

• They slow down the execution of functions.

• They help in creating private variables.

• They prevent functions from being reused.

• They make all variables global.

What is a common use case for closures?

• To make functions run in parallel.

• To prevent any function execution.

• To encapsulate data and create private variables.

• To create global variables.