[doc] include full options for createWriteStream?

[DTrejo]

Currently the docs say that these are the defaults for createWriteStream:

{ flags: 'w',
  encoding: null,
  mode: 0666 }

The true defaults are the following:

{ flags: 'w',

  // see https://github.com/joyent/node/blob/master/lib/fs.js#L1537
+  encoding: 'binary',

  // mixed in by https://github.com/joyent/node/blob/master/lib/fs.js#L1547
+  fd: null, // when passed in leads to same behavior as createReadStream's `fd` arg

  mode: 0666 
}

Shall I send in a pull request for the following?

1. add the fd argument
2. change to encoding: 'binary' for both read and write streams
3. Give an updated list of allowed encodings, along with explanations if needed:

via https://github.com/joyent/node/blob/master/lib/buffer.js#L278

    case 'hex':
    case 'utf8':
    case 'utf-8':
    case 'ascii':
    case 'binary':
    case 'base64':
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
    case 'raw':

Thanks for the feedback — don't want to write things and have them be wrong or never merged!

David Trejo

[mscdex]

WriteStream's encoding is not actually used anywhere. It should be removed.

[chrisdickinson]

The fd portion of this issue is addressed by #8001. Encoding is handled by the stream interface now -- closing this issue. Feel free to comment and I can reopen if I'm mistaken! Thanks.