string_decoder

The string_decoder module provides a way to decode Buffer objects into strings without breaking multibyte characters. Useful when streaming text data.

API Surface

Class: StringDecoder

  • new StringDecoder([encoding]) — default utf8.
  • .write(buffer) — returns string decoded from buffer.
  • .end([buffer]) — flush remaining input and end decoding.

Supported encodings: utf8, utf16le, base64.

Examples (English only)

const { StringDecoder } = require("string_decoder");
const decoder = new StringDecoder("utf8");

const buf1 = Buffer.from([0xe0, 0xa4, 0xa8]); // incomplete UTF-8 char
const buf2 = Buffer.from([0xa6]);

console.log(decoder.write(buf1)); // empty, waiting for completion
console.log(decoder.write(buf2)); // outputs proper char (e.g., 'न')

// End flush
console.log(decoder.end());

Notes

  • Unlike buf.toString(), StringDecoder preserves whole characters across chunk boundaries.
  • Useful when reading text from streams in arbitrary-sized chunks.
  • Always call .end() at the end of input to flush buffered bytes.