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Node.js v7.5.1-nightly2017020113a024d531 Documentation
Table of Contents
TTY#
Stability: 2 - Stable
The tty
module provides the tty.ReadStream
and tty.WriteStream
classes.
In most cases, it will not be necessary or possible to use this module directly.
However, it can be accessed using:
const tty = require('tty');
When Node.js detects that it is being run inside a text terminal ("TTY")
context, the process.stdin
will, by default, be initialized as an instance of
tty.ReadStream
and both process.stdout
and process.stderr
will, by
default be instances of tty.WriteStream
. The preferred method of determining
whether Node.js is being run within a TTY context is to check that the value of
the process.stdout.isTTY
property is true
:
$ node -p -e "Boolean(process.stdout.isTTY)"
true
$ node -p -e "Boolean(process.stdout.isTTY)" | cat
false
In most cases, there should be little to no reason for an application to
create instances of the tty.ReadStream
and tty.WriteStream
classes.
Class: tty.ReadStream#
The tty.ReadStream
class is a subclass of net.Socket
that represents the
readable side of a TTY. In normal circumstances process.stdin
will be the
only tty.ReadStream
instance in a Node.js process and there should be no
reason to create additional instances.
readStream.isRaw#
A boolean
that is true
if the TTY is currently configured to operate as a
raw device. Defaults to false
.
readStream.setRawMode(mode)#
Allows configuration of tty.ReadStream
so that it operates as a raw device.
When in raw mode, input is always available character-by-character, not
including modifiers. Additionally, all special processing of characters by the
terminal is disabled, including echoing input characters.
Note that CTRL
+C
will no longer cause a SIGINT
when in this mode.
mode
<boolean> Iftrue
, configures thetty.ReadStream
to operate as a raw device. Iffalse
, configures thetty.ReadStream
to operate in its default mode. ThereadStream.isRaw
property will be set to the resulting mode.
Class: tty.WriteStream#
The tty.WriteStream
class is a subclass of net.Socket
that represents the
writable side of a TTY. In normal circumstances, process.stdout
and
process.stderr
will be the only tty.WriteStream
instances created for a
Node.js process and there should be no reason to create additional instances.
Event: 'resize'#
The 'resize'
event is emitted whenever either of the writeStream.columns
or writeStream.rows
properties have changed. No arguments are passed to the
listener callback when called.
process.stdout.on('resize', () => {
console.log('screen size has changed!');
console.log(`${process.stdout.columns}x${process.stdout.rows}`);
});
writeStream.columns#
A number
specifying the number of columns the TTY currently has. This property
is updated whenever the 'resize'
event is emitted.
writeStream.rows#
A number
specifying the number of rows the TTY currently has. This property
is updated whenever the 'resize'
event is emitted.
tty.isatty(fd)#
fd
<number> A numeric file descriptor
The tty.isatty()
method returns true
if the given fd
is associated with
a TTY and false
if is not.