Function WriteStream

lib/internal/fs/streams.js:319–394

(path, options)

});

function WriteStream(path, options) {
  if (!(this instanceof WriteStream))
    return new WriteStream(path, options);

  options = copyObject(getOptions(options, kEmptyObject));

  // Only buffers are supported.
  options.decodeStrings = true;

  if (options.fd == null) {
    this.fd = null;
    this[kFs] = options.fs || fs;
    validateFunction(this[kFs].open, 'options.fs.open');

    // Path will be ignored when fd is specified, so it can be falsy
    this.path = toPathIfFileURL(path);
    this.flags = options.flags === undefined ? 'w' : options.flags;
    this.mode = options.mode === undefined ? 0o666 : options.mode;

    validatePath(this.path);
  } else {
    this.fd = getValidatedFd(importFd(this, options));
  }

  options.autoDestroy = options.autoClose === undefined ?
    true : options.autoClose;

  if (!this[kFs].write && !this[kFs].writev) {
    throw new ERR_INVALID_ARG_TYPE('options.fs.write', 'function',
                                   this[kFs].write);
  }

  if (this[kFs].write) {
    validateFunction(this[kFs].write, 'options.fs.write');
  }

  if (this[kFs].writev) {
    validateFunction(this[kFs].writev, 'options.fs.writev');
  }

  if (options.autoDestroy) {
    validateFunction(this[kFs].close, 'options.fs.close');
  }

  this.flush = options.flush;
  if (this.flush == null) {
    this.flush = false;
  } else {
    validateBoolean(this.flush, 'options.flush');
    validateFunction(this[kFs].fsync, 'options.fs.fsync');
  }

  // It's enough to override either, in which case only one will be used.
  if (!this[kFs].write) {
    this._write = null;
  }
  if (!this[kFs].writev) {
    this._writev = null;