Try-catch for synchronous errors in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to catch errors thrown inside the try block.

Node.js

try {
  JSON.parse('invalid json');
} catch ([1]) {
  console.log('Error caught');
}

Drag options to blanks, or click blank then click option'

Ae

Berr

Cerror

Dexception

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving the catch parentheses empty

Using a reserved word as the error variable

The catch block receives the error object as a parameter. Here, e is a common short name for the error.

2fill in blank

medium

Complete the code to throw a custom error inside the try block.

Node.js

try {
  throw new [1]('Something went wrong');
} catch (e) {
  console.log(e.message);
}

Drag options to blanks, or click blank then click option'

AError

BException

CSyntaxError

DTypeError

Attempts:

3 left

💡 Hint

Common Mistakes

Using Exception which is not a built-in JavaScript error class

Using specific error types when a general error is intended

Error is the base class for errors in JavaScript. Throwing new Error() creates a general error.

3fill in blank

hard

Fix the error in the catch block parameter to properly catch the error.

Node.js

try {
  JSON.parse('bad');
} catch [1] {
  console.log('Caught an error');
}

Drag options to blanks, or click blank then click option'

Aerror

B[error]

C(error)

D{error}

Attempts:

3 left

💡 Hint

Common Mistakes

Using square or curly brackets instead of parentheses

Omitting parentheses entirely

The catch block must have parentheses around the error parameter, like (error).

4fill in blank

hard

Fill both blanks to catch a TypeError and log its message.

Node.js

try {
  null.[1]();
} catch (e) {
  if (e instanceof [2]) {
    console.log(e.message);
  }
}

Drag options to blanks, or click blank then click option'

AtoString

BTypeError

CReferenceError

Dcall

Attempts:

3 left

💡 Hint

Common Mistakes

Using a method that exists on null

Checking for the wrong error type

Calling toString on null causes a TypeError. The catch block checks for that error type.

5fill in blank

hard

Fill all three blanks to create a try-catch that throws and catches a SyntaxError.

Node.js

try {
  throw new [1]('Invalid syntax');
} catch ([2]) {
  if ([2] instanceof [3]) {
    console.log([2].message);
  }
}

Drag options to blanks, or click blank then click option'

ASyntaxError

Berr

CError

De

Attempts:

3 left

💡 Hint

Common Mistakes

Using a generic Error instead of SyntaxError

Using inconsistent variable names in catch and inside the block

The code throws a SyntaxError, catches it as e, and checks if e is an instance of SyntaxError.