How to fix Error: The encoding is invalid (string decoder unsupported encoding) in Node.js

const { StringDecoder } = require('string_decoder');
const decoder = new StringDecoder('utf8');  // Correct
// const decoder = new StringDecoder('utf-8');  // Also works

const { StringDecoder } = require('string_decoder');

const encodingToUse = 'utf8';

if (Buffer.isEncoding(encodingToUse)) {
  const decoder = new StringDecoder(encodingToUse);
  console.log('Encoding is valid');
} else {
  console.error(`Encoding '${encodingToUse}' is not supported`);
}

const { StringDecoder } = require('string_decoder');

// Example: encoding from environment variable or config
const encoding = process.env.FILE_ENCODING || 'utf8';

if (!Buffer.isEncoding(encoding)) {
  throw new Error(`Invalid encoding: ${encoding}. Supported: ${Buffer.encodingLength ? 'utf8, utf16le, latin1, ascii, base64, hex' : 'check Node.js docs'}`);
}

const decoder = new StringDecoder(encoding);

npm install iconv-lite

const iconv = require('iconv-lite');

// Convert a buffer from Windows-1252 to UTF-8
const buffer = Buffer.from([0xE9, 0xE0]); // Windows-1252 bytes
const str = iconv.decode(buffer, 'win1252');
console.log(str);  // Output: éà

// Or encode a string to a specific encoding
const encoded = iconv.encode('Hello', 'shift_jis');

const { StringDecoder } = require('string_decoder');
const fs = require('fs');

// Example: Reading a UTF-8 encoded file
const readable = fs.createReadStream('file.txt', { encoding: 'utf8' });
const decoder = new StringDecoder('utf8');

readable.on('data', (chunk) => {
  const text = decoder.write(chunk);
  console.log(text);
});

readable.on('end', () => {
  const remaining = decoder.end();
  if (remaining) console.log(remaining);
});