What are some advanced JavaScript interview questions?

What are some advanced JavaScript interview questions I should prepare for?

Here are a few advanced JavaScript interview questions you might encounter:

1. Explain the concept of closures and provide an example.
2. What is the difference between 'null' and 'undefined'?
3. Can you explain the event loop in JavaScript?

Can you explain closures with an example?

Sure! A closure is a function that retains access to its lexical scope, even when the function is executed outside that scope. For example:

function outerFunction() {
    let outerVariable = 'I am outside!';
    function innerFunction() {
        console.log(outerVariable);
    }
    return innerFunction;
}

const myInnerFunction = outerFunction();
myInnerFunction(); // Outputs: I am outside!

What about the event loop? Can you explain that too?

Absolutely! The event loop is a mechanism that allows JavaScript to perform non-blocking I/O operations. It works with the call stack and the message queue. When a function is called, it gets pushed onto the call stack. If it encounters an asynchronous operation, it gets sent to the message queue. Once the call stack is empty, the event loop picks the next function from the message queue and pushes it onto the call stack for execution.