TTY

Stability: 2 - Unstable

The tty module houses the tty.ReadStream and tty.WriteStream classes. In
most cases, you will not need to use this module directly.

When node detects that it is being run inside a TTY context, then process.stdin
will be a tty.ReadStream instance and process.stdout will be
a tty.WriteStream instance. The preferred way to check if node is being run in
a TTY context is to check process.stdout.isTTY:

$ node -p -e "Boolean(process.stdout.isTTY)"
true
$ node -p -e "Boolean(process.stdout.isTTY)" | cat
false

tty.isatty(fd)

Returns true or false depending on if the fd is associated with a
terminal.

tty.setRawMode(mode)

Deprecated. Use tty.ReadStream#setRawMode()
(i.e. process.stdin.setRawMode()) instead.

Class: ReadStream

A net.Socket subclass that represents the readable portion of a tty. In normal
circumstances, process.stdin will be the only tty.ReadStream instance in any
node program (only when isatty(0) is true).

rs.isRaw

A Boolean that is initialized to false. It represents the current “raw” state
of the tty.ReadStream instance.

rs.setRawMode(mode)

mode should be true or false. This sets the properties of the
tty.ReadStream to act either as a raw device or default. isRaw will be set
to the resulting mode.

Class: WriteStream

A net.Socket subclass that represents the writable portion of a tty. In normal
circumstances, process.stdout will be the only tty.WriteStream instance
ever created (and only when isatty(1) is true).

ws.columns

A Number that gives the number of columns the TTY currently has. This property
gets updated on “resize” events.

ws.rows

A Number that gives the number of rows the TTY currently has. This property
gets updated on “resize” events.

Event: ‘resize’

function () {}

Emitted by refreshSize() when either of the columns or rows properties
has changed.

process.stdout.on('resize', function() {
  console.log('screen size has changed!');
  console.log(process.stdout.columns + 'x' + process.stdout.rows);
});