winstonjs/winston · error · Error

options.stream is required.

Error message

options.stream is required.

What it means

The Stream transport wraps a caller-provided writable stream. The constructor throws this Error when options.stream is missing or is not recognized as a stream (checked with the is-stream helper). Unlike File, Stream has no fallback destination, so a valid stream is mandatory.

Source

Thrown at lib/winston/transports/stream.js:30

const os = require('os');
const TransportStream = require('winston-transport');

/**
 * Transport for outputting to any arbitrary stream.
 * @type {Stream}
 * @extends {TransportStream}
 */
module.exports = class Stream extends TransportStream {
  /**
   * Constructor function for the Console transport object responsible for
   * persisting log messages and metadata to a terminal or TTY.
   * @param {!Object} [options={}] - Options for this instance.
   */
  constructor(options = {}) {
    super(options);

    if (!options.stream || !isStream(options.stream)) {
      throw new Error('options.stream is required.');
    }

    // We need to listen for drain events when write() returns false. This can
    // make node mad at times.
    this._stream = options.stream;
    this._stream.setMaxListeners(Infinity);
    this.isObjectMode = options.stream._writableState.objectMode;
    this.eol = (typeof options.eol === 'string') ? options.eol : os.EOL;
  }

  /**
   * Core logging method exposed to Winston.
   * @param {Object} info - TODO: add param description.
   * @param {Function} callback - TODO: add param description.
   * @returns {undefined}
   */
  log(info, callback) {
    setImmediate(() => this.emit('logged', info));

View on GitHub (pinned to ff0b79de85)

Solutions

1. Pass an actual writable stream: new winston.transports.Stream({ stream: process.stdout }).
2. If you meant to log to a file by path, use winston.transports.File({ filename }) instead of Stream.
3. Verify the value passes a stream check (isStream / stream.writable) before constructing.

Example fix

// before
new winston.transports.Stream({ stream: '/var/log/app.log' }); // string, not a stream
// after
new winston.transports.File({ filename: '/var/log/app.log' });
// or
new winston.transports.Stream({ stream: process.stdout });

function requireWritableStream(s) {
  if (!s || typeof s.write !== 'function') {
    throw new TypeError('Stream transport requires a writable Node stream');
  }
  return s;
}
// new winston.transports.Stream({ stream: requireWritableStream(process.stdout) });

const isWritableStream = (s) => !!s && typeof s.write === 'function' && typeof s.on === 'function';

try {
  streamTransport = new winston.transports.Stream({ stream: target });
} catch (err) {
  if (err.message === 'options.stream is required.') {
    console.error('Expected a writable stream, got:', typeof target);
  }
  throw err;
}

When it happens

Trigger: new winston.transports.Stream({}) ; new winston.transports.Stream({ stream: someString }) ; passing a duplex-less value such as a plain object, a file path string, or an http.IncomingMessage (readable) where a writable stream is required.

Common situations: Passing a filename string expecting Stream to open it (use File transport instead); passing process.stdout without options wrapping (must be options.stream = process.stdout); passing a readline interface or socket that isStream does not recognize.

Understand the failure class

Background: "Must pass :limit option" / "Missing required option" — required option errors explained — this error's family across 41 libraries.

Related errors

• Cannot make set from type other than Array of string element
• Cannot log to file without filename or stream.
• { %s } was removed in winston@3.0.0.
• { %s } was removed in winston@3.0.0. Use a custom winston.fo
• Logger is required to handle exceptions

AI-assisted analysis of winstonjs/winston@ff0b79de85 (2026-08-31). Data as JSON: /api/errors/6c8030d4e421fc7d. Report an issue: GitHub.