How do I handle null and undefined in JavaScript?

What is the difference between null and undefined in JavaScript?

In JavaScript, null is an intentional absence of any object value, while undefined means a variable has been declared but not assigned a value.

How can I check if a variable is null or undefined?

You can use the strict equality operator: if (variable === null || variable === undefined). Alternatively, you can use if (variable == null) to check for both.

What happens if I try to access a property of an undefined variable?

If you try to access a property of an undefined variable, it will throw a TypeError. It's best to check if the variable is defined first.

Can I use the nullish coalescing operator with these values?

Yes! The nullish coalescing operator (??) allows you to provide a default value when the left-hand side is null or undefined.