{ "type": "module", "source": "doc/api/tty.md", "modules": [ { "textRaw": "TTY", "name": "tty", "introduced_in": "v0.10.0", "type": "module", "stability": 2, "stabilityText": "Stable", "desc": "

The node:tty module provides the tty.ReadStream and tty.WriteStream\nclasses. In most cases, it will not be necessary or possible to use this module\ndirectly. However, it can be accessed using:

const tty = require('node:tty');\n

When Node.js detects that it is being run with a text terminal (\"TTY\")\nattached, process.stdin will, by default, be initialized as an instance of\ntty.ReadStream and both process.stdout and process.stderr will, by\ndefault, be instances of tty.WriteStream. The preferred method of determining\nwhether Node.js is being run within a TTY context is to check that the value of\nthe process.stdout.isTTY property is true:

$ node -p -e \"Boolean(process.stdout.isTTY)\"\ntrue\n$ node -p -e \"Boolean(process.stdout.isTTY)\" | cat\nfalse\n

In most cases, there should be little to no reason for an application to\nmanually create instances of the tty.ReadStream and tty.WriteStream\nclasses.

", "classes": [ { "textRaw": "Class: `tty.ReadStream`", "name": "tty.ReadStream", "type": "class", "meta": { "added": [ "v0.5.8" ], "changes": [] }, "desc": "

Extends: net.Socket

Represents the readable side of a TTY. In normal circumstances\nprocess.stdin will be the only tty.ReadStream instance in a Node.js\nprocess and there should be no reason to create additional instances.

", "properties": [ { "textRaw": "`readStream.isRaw`", "name": "isRaw", "type": "property", "meta": { "added": [ "v0.7.7" ], "changes": [] }, "desc": "

A boolean that is true if the TTY is currently configured to operate as a\nraw device.

This flag is always false when a process starts, even if the terminal is\noperating in raw mode. Its value will change with subsequent calls to\nsetRawMode.

" }, { "textRaw": "`readStream.isTTY`", "name": "isTTY", "type": "property", "meta": { "added": [ "v0.5.8" ], "changes": [] }, "desc": "

A boolean that is always true for tty.ReadStream instances.

" }, { "textRaw": "{boolean | string}", "name": "rawMode", "type": "boolean | string", "meta": { "added": [ "v26.8.0" ], "changes": [] }, "desc": "

The current raw mode for the tty.ReadStream. This is false when the stream\nis in its default mode, 'raw' when raw input mode is enabled, and 'io' when\nbinary-safe I/O mode is enabled.

" } ], "methods": [ { "textRaw": "`readStream.setRawMode(mode)`", "name": "setRawMode", "type": "method", "meta": { "added": [ "v0.7.7" ], "changes": [ { "version": "v26.8.0", "pr-url": "https://github.com/nodejs/node/pull/64140", "description": "The `mode` argument supports `'raw'` and `'io'`." } ] }, "signatures": [ { "params": [ { "textRaw": "`mode` {boolean | string} If `true` or `'raw'`, configures the `tty.ReadStream` to operate as a raw device. If `'io'`, configures the `tty.ReadStream` to operate in binary-safe I/O mode. If `false`, configures the `tty.ReadStream` to operate in its default mode. The `readStream.isRaw` property will be set to whether the stream is in raw mode, and the `readStream.rawMode` property will be set to the resulting mode.", "name": "mode", "type": "boolean | string", "desc": "If `true` or `'raw'`, configures the `tty.ReadStream` to operate as a raw device. If `'io'`, configures the `tty.ReadStream` to operate in binary-safe I/O mode. If `false`, configures the `tty.ReadStream` to operate in its default mode. The `readStream.isRaw` property will be set to whether the stream is in raw mode, and the `readStream.rawMode` property will be set to the resulting mode." } ], "return": { "textRaw": "Returns: {this} The read stream instance.", "name": "return", "type": "this", "desc": "The read stream instance." } } ], "desc": "

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\nincluding modifiers. Additionally, all special processing of input characters\nby the terminal is disabled, including echoing input\ncharacters. Ctrl+C will no longer cause a SIGINT when\nin this mode. This mode does not affect terminal output processing, such as\nnewline translation on Unix terminals.

On Windows, setRawMode() requires write permission to the console input\nbuffer. When opening \"\\\\\\\\.\\\\CONIN$\" with the fs.open() family of APIs\n(for passing into new tty.ReadStream()), be sure to use a read/write flag\nsuch as 'r+'.

When in binary-safe I/O mode, terminal output processing is also disabled.\nThis corresponds to libuv's UV_TTY_MODE_IO mode and is not supported on\nWindows.

" } ] }, { "textRaw": "Class: `tty.WriteStream`", "name": "tty.WriteStream", "type": "class", "meta": { "added": [ "v0.5.8" ], "changes": [] }, "desc": "

Extends: net.Socket

Represents the writable side of a TTY. In normal circumstances,\nprocess.stdout and process.stderr will be the only\ntty.WriteStream instances created for a Node.js process and there\nshould be no reason to create additional instances.

", "signatures": [ { "textRaw": "`new tty.ReadStream(fd[, options])`", "name": "tty.ReadStream", "type": "ctor", "meta": { "added": [ "v0.5.8" ], "changes": [ { "version": "v0.9.4", "description": "The `options` argument is supported." } ] }, "params": [ { "textRaw": "`fd` {number} A file descriptor associated with a TTY.", "name": "fd", "type": "number", "desc": "A file descriptor associated with a TTY." }, { "textRaw": "`options` {Object} Options passed to parent `net.Socket`, see `options` of `net.Socket` constructor.", "name": "options", "type": "Object", "desc": "Options passed to parent `net.Socket`, see `options` of `net.Socket` constructor.", "optional": true } ], "return": { "textRaw": "Returns: {tty.ReadStream}", "name": "return", "type": "tty.ReadStream" }, "desc": "

Creates a ReadStream for fd associated with a TTY.

" }, { "textRaw": "`new tty.WriteStream(fd)`", "name": "tty.WriteStream", "type": "ctor", "meta": { "added": [ "v0.5.8" ], "changes": [] }, "params": [ { "textRaw": "`fd` {number} A file descriptor associated with a TTY.", "name": "fd", "type": "number", "desc": "A file descriptor associated with a TTY." } ], "return": { "textRaw": "Returns: {tty.WriteStream}", "name": "return", "type": "tty.WriteStream" }, "desc": "

Creates a WriteStream for fd associated with a TTY.

" } ], "events": [ { "textRaw": "Event: `'resize'`", "name": "resize", "type": "event", "meta": { "added": [ "v0.7.7" ], "changes": [] }, "params": [], "desc": "

The 'resize' event is emitted whenever either of the writeStream.columns\nor writeStream.rows properties have changed. No arguments are passed to the\nlistener callback when called.

process.stdout.on('resize', () => {\n  console.log('screen size has changed!');\n  console.log(`${process.stdout.columns}x${process.stdout.rows}`);\n});\n

" } ], "methods": [ { "textRaw": "`writeStream.clearLine(dir[, callback])`", "name": "clearLine", "type": "method", "meta": { "added": [ "v0.7.7" ], "changes": [ { "version": "v12.7.0", "pr-url": "https://github.com/nodejs/node/pull/28721", "description": "The stream's write() callback and return value are exposed." } ] }, "signatures": [ { "params": [ { "textRaw": "`dir` {number}", "name": "dir", "type": "number", "options": [ { "textRaw": "`-1`: to the left from cursor", "name": "-1", "desc": "to the left from cursor" }, { "textRaw": "`1`: to the right from cursor", "name": "1", "desc": "to the right from cursor" }, { "textRaw": "`0`: the entire line", "name": "0", "desc": "the entire line" } ] }, { "textRaw": "`callback` {Function} Invoked once the operation completes.", "name": "callback", "type": "Function", "desc": "Invoked once the operation completes.", "optional": true } ], "return": { "textRaw": "Returns: {boolean} `false` if the stream wishes for the calling code to wait for the `'drain'` event to be emitted before continuing to write additional data; otherwise `true`.", "name": "return", "type": "boolean", "desc": "`false` if the stream wishes for the calling code to wait for the `'drain'` event to be emitted before continuing to write additional data; otherwise `true`." } } ], "desc": "

writeStream.clearLine() clears the current line of this WriteStream in a\ndirection identified by dir.

" }, { "textRaw": "`writeStream.clearScreenDown([callback])`", "name": "clearScreenDown", "type": "method", "meta": { "added": [ "v0.7.7" ], "changes": [ { "version": "v12.7.0", "pr-url": "https://github.com/nodejs/node/pull/28721", "description": "The stream's write() callback and return value are exposed." } ] }, "signatures": [ { "params": [ { "textRaw": "`callback` {Function} Invoked once the operation completes.", "name": "callback", "type": "Function", "desc": "Invoked once the operation completes.", "optional": true } ], "return": { "textRaw": "Returns: {boolean} `false` if the stream wishes for the calling code to wait for the `'drain'` event to be emitted before continuing to write additional data; otherwise `true`.", "name": "return", "type": "boolean", "desc": "`false` if the stream wishes for the calling code to wait for the `'drain'` event to be emitted before continuing to write additional data; otherwise `true`." } } ], "desc": "

writeStream.clearScreenDown() clears this WriteStream from the current\ncursor down.

" }, { "textRaw": "`writeStream.cursorTo(x[, y][, callback])`", "name": "cursorTo", "type": "method", "meta": { "added": [ "v0.7.7" ], "changes": [ { "version": "v12.7.0", "pr-url": "https://github.com/nodejs/node/pull/28721", "description": "The stream's write() callback and return value are exposed." } ] }, "signatures": [ { "params": [ { "textRaw": "`x` {number}", "name": "x", "type": "number" }, { "textRaw": "`y` {number}", "name": "y", "type": "number", "optional": true }, { "textRaw": "`callback` {Function} Invoked once the operation completes.", "name": "callback", "type": "Function", "desc": "Invoked once the operation completes.", "optional": true } ], "return": { "textRaw": "Returns: {boolean} `false` if the stream wishes for the calling code to wait for the `'drain'` event to be emitted before continuing to write additional data; otherwise `true`.", "name": "return", "type": "boolean", "desc": "`false` if the stream wishes for the calling code to wait for the `'drain'` event to be emitted before continuing to write additional data; otherwise `true`." } } ], "desc": "

writeStream.cursorTo() moves this WriteStream's cursor to the specified\nposition.

" }, { "textRaw": "`writeStream.getColorDepth([env])`", "name": "getColorDepth", "type": "method", "meta": { "added": [ "v9.9.0" ], "changes": [] }, "signatures": [ { "params": [ { "textRaw": "`env` {Object} An object containing the environment variables to check. This enables simulating the usage of a specific terminal. **Default:** `process.env`.", "name": "env", "type": "Object", "default": "`process.env`", "desc": "An object containing the environment variables to check. This enables simulating the usage of a specific terminal.", "optional": true } ], "return": { "textRaw": "Returns: {number}", "name": "return", "type": "number" } } ], "desc": "

Returns:

1 for 2,
4 for 16,
8 for 256,
24 for 16,777,216 colors supported.

Use this to determine what colors the terminal supports. Due to the nature of\ncolors in terminals it is possible to either have false positives or false\nnegatives. It depends on process information and the environment variables that\nmay lie about what terminal is used.\nIt is possible to pass in an env object to simulate the usage of a specific\nterminal. This can be useful to check how specific environment settings behave.

To enforce a specific color support, use one of the below environment settings.

2 colors: FORCE_COLOR = 0 (Disables colors)
16 colors: FORCE_COLOR = 1
256 colors: FORCE_COLOR = 2
16,777,216 colors: FORCE_COLOR = 3

Disabling color support is also possible by using the NO_COLOR and\nNODE_DISABLE_COLORS environment variables.

" }, { "textRaw": "`writeStream.getWindowSize()`", "name": "getWindowSize", "type": "method", "meta": { "added": [ "v0.7.7" ], "changes": [] }, "signatures": [ { "params": [], "return": { "textRaw": "Returns: {number[]}", "name": "return", "type": "number[]" } } ], "desc": "

writeStream.getWindowSize() returns the size of the TTY\ncorresponding to this WriteStream. The array is of the type\n[numColumns, numRows] where numColumns and numRows represent the number\nof columns and rows in the corresponding TTY.

" }, { "textRaw": "`writeStream.hasColors([count][, env])`", "name": "hasColors", "type": "method", "meta": { "added": [ "v11.13.0", "v10.16.0" ], "changes": [] }, "signatures": [ { "params": [ { "textRaw": "`count` {integer} The number of colors that are requested (minimum 2). **Default:** 16.", "name": "count", "type": "integer", "default": "16", "desc": "The number of colors that are requested (minimum 2).", "optional": true }, { "textRaw": "`env` {Object} An object containing the environment variables to check. This enables simulating the usage of a specific terminal. **Default:** `process.env`.", "name": "env", "type": "Object", "default": "`process.env`", "desc": "An object containing the environment variables to check. This enables simulating the usage of a specific terminal.", "optional": true } ], "return": { "textRaw": "Returns: {boolean}", "name": "return", "type": "boolean" } } ], "desc": "

Returns true if the writeStream supports at least as many colors as provided\nin count. Minimum support is 2 (black and white).

This has the same false positives and negatives as described in\nwriteStream.getColorDepth().

process.stdout.hasColors();\n// Returns true or false depending on if `stdout` supports at least 16 colors.\nprocess.stdout.hasColors(256);\n// Returns true or false depending on if `stdout` supports at least 256 colors.\nprocess.stdout.hasColors({ TMUX: '1' });\n// Returns true.\nprocess.stdout.hasColors(2 ** 24, { TMUX: '1' });\n// Returns false (the environment setting pretends to support 2 ** 8 colors).\n

" }, { "textRaw": "`writeStream.moveCursor(dx, dy[, callback])`", "name": "moveCursor", "type": "method", "meta": { "added": [ "v0.7.7" ], "changes": [ { "version": "v12.7.0", "pr-url": "https://github.com/nodejs/node/pull/28721", "description": "The stream's write() callback and return value are exposed." } ] }, "signatures": [ { "params": [ { "textRaw": "`dx` {number}", "name": "dx", "type": "number" }, { "textRaw": "`dy` {number}", "name": "dy", "type": "number" }, { "textRaw": "`callback` {Function} Invoked once the operation completes.", "name": "callback", "type": "Function", "desc": "Invoked once the operation completes.", "optional": true } ], "return": { "textRaw": "Returns: {boolean} `false` if the stream wishes for the calling code to wait for the `'drain'` event to be emitted before continuing to write additional data; otherwise `true`.", "name": "return", "type": "boolean", "desc": "`false` if the stream wishes for the calling code to wait for the `'drain'` event to be emitted before continuing to write additional data; otherwise `true`." } } ], "desc": "

writeStream.moveCursor() moves this WriteStream's cursor relative to its\ncurrent position.

" } ], "properties": [ { "textRaw": "`writeStream.columns`", "name": "columns", "type": "property", "meta": { "added": [ "v0.7.7" ], "changes": [] }, "desc": "

A number specifying the number of columns the TTY currently has. This property\nis updated whenever the 'resize' event is emitted.

" }, { "textRaw": "`writeStream.isTTY`", "name": "isTTY", "type": "property", "meta": { "added": [ "v0.5.8" ], "changes": [] }, "desc": "

A boolean that is always true.

" }, { "textRaw": "`writeStream.rows`", "name": "rows", "type": "property", "meta": { "added": [ "v0.7.7" ], "changes": [] }, "desc": "

A number specifying the number of rows the TTY currently has. This property\nis updated whenever the 'resize' event is emitted.

" } ] } ], "methods": [ { "textRaw": "`tty.isatty(fd)`", "name": "isatty", "type": "method", "meta": { "added": [ "v0.5.8" ], "changes": [] }, "signatures": [ { "params": [ { "textRaw": "`fd` {number} A numeric file descriptor", "name": "fd", "type": "number", "desc": "A numeric file descriptor" } ], "return": { "textRaw": "Returns: {boolean}", "name": "return", "type": "boolean" } } ], "desc": "

The tty.isatty() method returns true if the given fd is associated with\na TTY and false if it is not, including whenever fd is not a non-negative\ninteger.

" } ], "displayName": "TTY" } ] }