Reading and writing buffer data in Node.js - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Buffer in Node.js?

A Buffer is a special object in Node.js used to store raw binary data. It allows you to work with streams of bytes directly, like reading files or network data.

beginner

How do you create a Buffer from a string in Node.js?

Use Buffer.from('your string') to create a Buffer containing the bytes of the string.

intermediate

Which method reads an unsigned 8-bit integer from a Buffer at a specific offset?

The method buffer.readUInt8(offset) reads an unsigned 8-bit integer from the Buffer at the given offset.

intermediate

How do you write a 16-bit unsigned integer to a Buffer at a specific offset?

Use buffer.writeUInt16LE(value, offset) to write a 16-bit unsigned integer in little-endian format at the offset.

advanced

Why is it important to specify endianness when reading or writing multi-byte values in a Buffer?

Endianness determines byte order. Specifying it ensures data is interpreted correctly across different systems, preventing errors in reading or writing multi-byte numbers.

Which method creates a Buffer from a string in Node.js?

A new Buffer('text')

B Buffer.from('text')

C Buffer.create('text')

D Buffer.string('text')

Buffer.from('text') is the modern and safe way to create a Buffer from a string.

What does buffer.readUInt8(0) return?

A An unsigned 8-bit integer from the start of the buffer

B A signed 8-bit integer from the start of the buffer

C A string from the buffer

D The length of the buffer

readUInt8 reads an unsigned 8-bit integer at the specified offset.

Which method writes a 32-bit unsigned integer in little-endian format to a Buffer?

A buffer.writeUInt32LE(value, offset)

B buffer.writeUInt32BE(value, offset)

C buffer.writeInt32LE(value, offset)

D buffer.writeInt32BE(value, offset)

writeUInt32LE writes a 32-bit unsigned integer in little-endian byte order.

What is the default encoding when converting a Buffer to a string using buffer.toString()?

A hex

B ascii

C base64

D utf8

utf8 is the default encoding for buffer.toString() in Node.js.

Why should you be careful with the offset when reading or writing Buffer data?

A Offset controls the Buffer size

B Because offset changes the encoding

C To avoid reading or writing outside the Buffer bounds causing errors

D Offset is only used for strings

Using an invalid offset can cause runtime errors or corrupt data.

Explain how to read and write numeric data using Node.js Buffers. Include how to handle byte order.

Think about how bytes are stored and accessed in memory.

Describe how to convert a string to a Buffer and back to a string in Node.js.

Consider how text is stored as bytes.