Node.js Buffer: An Introduction to Handling Binary Data

In Node.js, when dealing with binary data such as images and network transmission data, the Buffer is a core tool for efficiently storing and manipulating byte streams. It is a fixed-length array of bytes, where each element is an integer between 0 and 255. Buffer cannot be dynamically expanded and serves as the foundation for I/O operations. There are three ways to create a Buffer: `Buffer.alloc(size)` (specifies the length and initializes it to 0), `Buffer.from(array)` (converts an array to a Buffer), and `Buffer.from(string, encoding)` (converts a string to a Buffer, requiring an encoding like utf8 to be specified). A Buffer can read and write bytes via indices, obtain its length using the `length` property, convert to a string with `buf.toString(encoding)`, and concatenate Buffers using `Buffer.concat([buf1, buf2])`. Common methods include `write()` (to write a string) and `slice()` (to extract a portion). Applications include file processing, network communication, and database BLOB operations. It is important to note encoding consistency (e.g., matching utf8 and base64 conversions), avoid overflow (values exceeding 255 will be truncated), and manage off-heap memory reasonably to prevent leaks. Mastering Buffer is crucial for understanding Node.js binary data processing.