What are the best practices for using null and undefined in JavaScript?

What are the best practices for using null and undefined in JavaScript?

In JavaScript, it's important to use null and undefined correctly to avoid bugs. Use null to represent intentional absence of value, and undefined for uninitialized variables.

Can you give me examples of when to use each?

Sure! Use null when you want to explicitly indicate that a variable should have no value, like when resetting a form. Use undefined when a variable is declared but not assigned a value.

What about type checking? How can I check if a variable is null or undefined?

You can use the strict equality operator (===) to check for null and undefined. For example, if (myVar === null) checks for null, and if (myVar === undefined) checks for undefined.

Are there any pitfalls I should be aware of?

Yes, one common pitfall is using loose equality (==) which can lead to unexpected results. Always prefer strict equality to avoid confusion.