In Node.js, a buffer is a temporary storage area in memory used for storing raw binary data. It is a representation of fixed-size chunks of memory that can be allocated outside of the JavaScript engine's heap. Buffers are useful when working with binary data, such as reading from files or network sockets, or when interfacing with C/C++ libraries that deal with binary data.
Buffers can be created using the Buffer class, which is a built-in class provided by Node.js. You can create a buffer in several ways:
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Using a size in bytes:
const buf = Buffer.alloc(10); // creates a buffer of 10 bytes, filled with zeros
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From an array of integers:
const buf = Buffer.from([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]); // creates a buffer from array of integers
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From a string with encoding:
const buf = Buffer.from('buffer', 'utf-8'); // creates a buffer from string with specified encoding
Once you have a buffer, you can read from or write to it using various methods provided by the Buffer class, such as buf.write(), buf.toString(), buf.slice(), etc.
Buffers are particularly useful in scenarios where handling binary data efficiently is required, such as working with file systems, network protocols, cryptographic operations, and more. However, it's essential to use buffers carefully, as improper handling can lead to security vulnerabilities such as buffer overflows.