Buffer allocation and encoding in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to allocate a buffer of 10 bytes.

Node.js

const buf = Buffer.[1](10);

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

Aalloc

Bfrom

Cnew

Dcreate

Attempts:

3 left

💡 Hint

Common Mistakes

Using Buffer.from instead of Buffer.alloc

Trying to use 'new Buffer' which is deprecated

The Buffer.alloc(size) method creates a buffer of the specified size filled with zeros.

2fill in blank

medium

Complete the code to create a buffer from the string 'hello' using UTF-8 encoding.

Node.js

const buf = Buffer.from('hello', '[1]');

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

Abase64

Butf8

Cascii

Dhex

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ascii' which only supports basic English characters

Using 'base64' which is for encoded binary data, not plain text

The default and most common encoding for strings is utf8. It encodes characters as UTF-8 bytes.

3fill in blank

hard

Fix the error in the code to convert a buffer to a string with base64 encoding.

Node.js

const str = buf.toString('[1]');

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

Autf8

Bhex

Cbase64

Dascii

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'utf8' instead of 'base64' for encoding

Using 'hex' which produces hexadecimal string, not base64

To convert a buffer to a base64 encoded string, use buf.toString('base64').

4fill in blank

hard

Fill both blanks to create a buffer from a hex string and convert it back to a utf8 string.

Node.js

const buf = Buffer.[1]('68656c6c6f', '[2]');
const str = buf.toString('utf8');

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

Afrom

Balloc

Chex

Dutf8

Attempts:

3 left

💡 Hint

Common Mistakes

Using Buffer.alloc instead of Buffer.from

Using 'utf8' as input encoding for a hex string

Use Buffer.from to create a buffer from a string, specifying the input encoding as hex.

5fill in blank

hard

Fill all three blanks to allocate a buffer, write a string with utf8 encoding, and convert it to base64.

Node.js

const buf = Buffer.[1](6);
buf.write('hello', 0, [2], '[3]');
const base64 = buf.toString('base64');

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

Aalloc

B5

Cutf8

Dfrom

Attempts:

3 left

💡 Hint

Common Mistakes

Using Buffer.from instead of Buffer.alloc for fixed size buffer

Incorrect length parameter in write method

Wrong encoding name in write method

Allocate a buffer of size 6 with Buffer.alloc. Write the string 'hello' starting at offset 0, with length 5, using 'utf8' encoding. Then convert to base64 string.