Try–catch block in Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of a try–catch block in JavaScript?

A try–catch block is used to handle errors gracefully. The code inside the try block runs normally, but if an error happens, the catch block runs to handle that error without stopping the whole program.

beginner

What happens if no error occurs inside the try block?

If no error occurs, the code inside the catch block is skipped, and the program continues running after the try–catch block.

beginner

How do you access the error object inside the catch block?

You give a name to the error in parentheses after catch, like catch (error). Then you can use this name to get details about the error, for example, error.message.

intermediate

Can you use a try–catch block without a catch block in JavaScript?

No, in JavaScript, a try block must be followed by either a catch block, a finally block, or both. You cannot have a try block alone.

intermediate

What is the role of the finally block in a try–catch statement?

The finally block runs after the try and catch blocks, no matter what. It is used to run code that should always happen, like cleaning up resources.

What part of a try–catch block runs only if an error occurs?

A try block

B catch block

C finally block

D none

The catch block runs only when an error happens inside the try block.

Which keyword is used to define the block where you put code that might cause an error?

A catch

B finally

C try

D throw

The try keyword defines the block where you put code that might throw an error.

What will happen if an error occurs in the try block but there is no catch block?

A The error is automatically fixed

B The error is ignored

C The finally block runs

D The program crashes

Without a catch block, the error is not handled and will cause the program to crash.

Which block runs regardless of whether an error occurs or not?

A finally

B catch

C try

D throw

The finally block always runs after try and catch, no matter what.

How do you get the error message inside the catch block?

A Using error.message

B Using try.message

C Using catch.message

D Using finally.message

Inside catch, the error object is usually named (e.g., error), and you access the message with error.message.

Explain how a try–catch block helps in handling errors in JavaScript.

Think about what happens when code causes a problem.

Describe the difference between the catch and finally blocks in a try–catch statement.

One runs only on error, the other runs no matter what.