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      <details id="toc" open><summary>Table of contents</summary><ul>
<li><span class="stability_2"><a href="#tty_tty">TTY</a></span>
<ul>
<li><a href="#tty_class_tty_readstream">Class: <code>tty.ReadStream</code></a>
<ul>
<li><a href="#tty_readstream_israw"><code>readStream.isRaw</code></a></li>
<li><a href="#tty_readstream_istty"><code>readStream.isTTY</code></a></li>
<li><a href="#tty_readstream_setrawmode_mode"><code>readStream.setRawMode(mode)</code></a></li>
</ul>
</li>
<li><a href="#tty_class_tty_writestream">Class: <code>tty.WriteStream</code></a>
<ul>
<li><a href="#tty_event_resize">Event: <code>'resize'</code></a></li>
<li><a href="#tty_writestream_clearline_dir_callback"><code>writeStream.clearLine(dir[, callback])</code></a></li>
<li><a href="#tty_writestream_clearscreendown_callback"><code>writeStream.clearScreenDown([callback])</code></a></li>
<li><a href="#tty_writestream_columns"><code>writeStream.columns</code></a></li>
<li><a href="#tty_writestream_cursorto_x_y_callback"><code>writeStream.cursorTo(x[, y][, callback])</code></a></li>
<li><a href="#tty_writestream_getcolordepth_env"><code>writeStream.getColorDepth([env])</code></a></li>
<li><a href="#tty_writestream_getwindowsize"><code>writeStream.getWindowSize()</code></a></li>
<li><a href="#tty_writestream_hascolors_count_env"><code>writeStream.hasColors([count][, env])</code></a></li>
<li><a href="#tty_writestream_istty"><code>writeStream.isTTY</code></a></li>
<li><a href="#tty_writestream_movecursor_dx_dy_callback"><code>writeStream.moveCursor(dx, dy[, callback])</code></a></li>
<li><a href="#tty_writestream_rows"><code>writeStream.rows</code></a></li>
</ul>
</li>
<li><a href="#tty_tty_isatty_fd"><code>tty.isatty(fd)</code></a></li>
</ul>
</li>
</ul></details>

      <div id="apicontent">
        <h2>TTY<span><a class="mark" href="#tty_tty" id="tty_tty">#</a></span></h2>

<p></p><div class="api_stability api_stability_2"><a href="documentation.html#documentation_stability_index">Stability: 2</a> - Stable</div><p></p>
<p><strong>Source Code:</strong> <a href="https://github.com/nodejs/node/blob/v14.20.1/lib/tty.js">lib/tty.js</a></p>
<p>The <code>tty</code> module provides the <code>tty.ReadStream</code> and <code>tty.WriteStream</code> classes.
In most cases, it will not be necessary or possible to use this module directly.
However, it can be accessed using:</p>
<pre><code class="language-js"><span class="hljs-keyword">const</span> tty = <span class="hljs-built_in">require</span>(<span class="hljs-string">'tty'</span>);</code></pre>
<p>When Node.js detects that it is being run with a text terminal ("TTY")
attached, <a href="process.html#process_process_stdin"><code>process.stdin</code></a> will, by default, be initialized as an instance of
<code>tty.ReadStream</code> and both <a href="process.html#process_process_stdout"><code>process.stdout</code></a> and <a href="process.html#process_process_stderr"><code>process.stderr</code></a> will, by
default, be instances of <code>tty.WriteStream</code>. The preferred method of determining
whether Node.js is being run within a TTY context is to check that the value of
the <code>process.stdout.isTTY</code> property is <code>true</code>:</p>
<pre><code class="language-console"><span class="hljs-meta">$ </span><span class="language-bash">node -p -e <span class="hljs-string">"Boolean(process.stdout.isTTY)"</span></span>
true
<span class="hljs-meta">$ </span><span class="language-bash">node -p -e <span class="hljs-string">"Boolean(process.stdout.isTTY)"</span> | cat</span>
false</code></pre>
<p>In most cases, there should be little to no reason for an application to
manually create instances of the <code>tty.ReadStream</code> and <code>tty.WriteStream</code>
classes.</p>
<section><h3>Class: <code>tty.ReadStream</code><span><a class="mark" href="#tty_class_tty_readstream" id="tty_class_tty_readstream">#</a></span></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li>Extends: <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a></li>
</ul>
<p>Represents the readable side of a TTY. In normal circumstances
<a href="process.html#process_process_stdin"><code>process.stdin</code></a> will be the only <code>tty.ReadStream</code> instance in a Node.js
process and there should be no reason to create additional instances.</p>
<h4><code>readStream.isRaw</code><span><a class="mark" href="#tty_readstream_israw" id="tty_readstream_israw">#</a></span></h4>
<div class="api_metadata">
<span>Added in: v0.7.7</span>
</div>
<p>A <code>boolean</code> that is <code>true</code> if the TTY is currently configured to operate as a
raw device. Defaults to <code>false</code>.</p>
<h4><code>readStream.isTTY</code><span><a class="mark" href="#tty_readstream_istty" id="tty_readstream_istty">#</a></span></h4>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<p>A <code>boolean</code> that is always <code>true</code> for <code>tty.ReadStream</code> instances.</p>
<h4><code>readStream.setRawMode(mode)</code><span><a class="mark" href="#tty_readstream_setrawmode_mode" id="tty_readstream_setrawmode_mode">#</a></span></h4>
<div class="api_metadata">
<span>Added in: v0.7.7</span>
</div>
<ul>
<li><code>mode</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> If <code>true</code>, configures the <code>tty.ReadStream</code> to operate as a
raw device. If <code>false</code>, configures the <code>tty.ReadStream</code> to operate in its
default mode. The <code>readStream.isRaw</code> property will be set to the resulting
mode.</li>
<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this" class="type">&#x3C;this></a> The read stream instance.</li>
</ul>
<p>Allows configuration of <code>tty.ReadStream</code> so that it operates as a raw device.</p>
<p>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.
<kbd>Ctrl</kbd>+<kbd>C</kbd> will no longer cause a <code>SIGINT</code> when in this mode.</p>
</section><section><h3>Class: <code>tty.WriteStream</code><span><a class="mark" href="#tty_class_tty_writestream" id="tty_class_tty_writestream">#</a></span></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li>Extends: <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a></li>
</ul>
<p>Represents the writable side of a TTY. In normal circumstances,
<a href="process.html#process_process_stdout"><code>process.stdout</code></a> and <a href="process.html#process_process_stderr"><code>process.stderr</code></a> will be the only
<code>tty.WriteStream</code> instances created for a Node.js process and there
should be no reason to create additional instances.</p>
<h4>Event: <code>'resize'</code><span><a class="mark" href="#tty_event_resize" id="tty_event_resize">#</a></span></h4>
<div class="api_metadata">
<span>Added in: v0.7.7</span>
</div>
<p>The <code>'resize'</code> event is emitted whenever either of the <code>writeStream.columns</code>
or <code>writeStream.rows</code> properties have changed. No arguments are passed to the
listener callback when called.</p>
<pre><code class="language-js">process.<span class="hljs-property">stdout</span>.<span class="hljs-title function_">on</span>(<span class="hljs-string">'resize'</span>, <span class="hljs-function">() =></span> {
  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'screen size has changed!'</span>);
  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`<span class="hljs-subst">${process.stdout.columns}</span>x<span class="hljs-subst">${process.stdout.rows}</span>`</span>);
});</code></pre>
<h4><code>writeStream.clearLine(dir[, callback])</code><span><a class="mark" href="#tty_writestream_clearline_dir_callback" id="tty_writestream_clearline_dir_callback">#</a></span></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v12.7.0</td>
<td><p>The stream's write() callback and return value are exposed.</p></td></tr>
<tr><td>v0.7.7</td>
<td><p><span>Added in: v0.7.7</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>dir</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a>
<ul>
<li><code>-1</code>: to the left from cursor</li>
<li><code>1</code>: to the right from cursor</li>
<li><code>0</code>: the entire line</li>
</ul>
</li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> Invoked once the operation completes.</li>
<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> <code>false</code> if the stream wishes for the calling code to wait
for the <code>'drain'</code> event to be emitted before continuing to write additional
data; otherwise <code>true</code>.</li>
</ul>
<p><code>writeStream.clearLine()</code> clears the current line of this <code>WriteStream</code> in a
direction identified by <code>dir</code>.</p>
<h4><code>writeStream.clearScreenDown([callback])</code><span><a class="mark" href="#tty_writestream_clearscreendown_callback" id="tty_writestream_clearscreendown_callback">#</a></span></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v12.7.0</td>
<td><p>The stream's write() callback and return value are exposed.</p></td></tr>
<tr><td>v0.7.7</td>
<td><p><span>Added in: v0.7.7</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> Invoked once the operation completes.</li>
<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> <code>false</code> if the stream wishes for the calling code to wait
for the <code>'drain'</code> event to be emitted before continuing to write additional
data; otherwise <code>true</code>.</li>
</ul>
<p><code>writeStream.clearScreenDown()</code> clears this <code>WriteStream</code> from the current
cursor down.</p>
<h4><code>writeStream.columns</code><span><a class="mark" href="#tty_writestream_columns" id="tty_writestream_columns">#</a></span></h4>
<div class="api_metadata">
<span>Added in: v0.7.7</span>
</div>
<p>A <code>number</code> specifying the number of columns the TTY currently has. This property
is updated whenever the <code>'resize'</code> event is emitted.</p>
<h4><code>writeStream.cursorTo(x[, y][, callback])</code><span><a class="mark" href="#tty_writestream_cursorto_x_y_callback" id="tty_writestream_cursorto_x_y_callback">#</a></span></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v12.7.0</td>
<td><p>The stream's write() callback and return value are exposed.</p></td></tr>
<tr><td>v0.7.7</td>
<td><p><span>Added in: v0.7.7</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>x</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
<li><code>y</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> Invoked once the operation completes.</li>
<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> <code>false</code> if the stream wishes for the calling code to wait
for the <code>'drain'</code> event to be emitted before continuing to write additional
data; otherwise <code>true</code>.</li>
</ul>
<p><code>writeStream.cursorTo()</code> moves this <code>WriteStream</code>'s cursor to the specified
position.</p>
<h4><code>writeStream.getColorDepth([env])</code><span><a class="mark" href="#tty_writestream_getcolordepth_env" id="tty_writestream_getcolordepth_env">#</a></span></h4>
<div class="api_metadata">
<span>Added in: v9.9.0</span>
</div>
<ul>
<li><code>env</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> An object containing the environment variables to check. This
enables simulating the usage of a specific terminal. <strong>Default:</strong>
<code>process.env</code>.</li>
<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
</ul>
<p>Returns:</p>
<ul>
<li><code>1</code> for 2,</li>
<li><code>4</code> for 16,</li>
<li><code>8</code> for 256,</li>
<li><code>24</code> for 16,777,216</li>
</ul>
<p>colors supported.</p>
<p>Use this to determine what colors the terminal supports. Due to the nature of
colors in terminals it is possible to either have false positives or false
negatives. It depends on process information and the environment variables that
may lie about what terminal is used.
It is possible to pass in an <code>env</code> object to simulate the usage of a specific
terminal. This can be useful to check how specific environment settings behave.</p>
<p>To enforce a specific color support, use one of the below environment settings.</p>
<ul>
<li>2 colors: <code>FORCE_COLOR = 0</code> (Disables colors)</li>
<li>16 colors: <code>FORCE_COLOR = 1</code></li>
<li>256 colors: <code>FORCE_COLOR = 2</code></li>
<li>16,777,216 colors: <code>FORCE_COLOR = 3</code></li>
</ul>
<p>Disabling color support is also possible by using the <code>NO_COLOR</code> and
<code>NODE_DISABLE_COLORS</code> environment variables.</p>
<h4><code>writeStream.getWindowSize()</code><span><a class="mark" href="#tty_writestream_getwindowsize" id="tty_writestream_getwindowsize">#</a></span></h4>
<div class="api_metadata">
<span>Added in: v0.7.7</span>
</div>
<ul>
<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number[]></a></li>
</ul>
<p><code>writeStream.getWindowSize()</code> returns the size of the TTY
corresponding to this <code>WriteStream</code>. The array is of the type
<code>[numColumns, numRows]</code> where <code>numColumns</code> and <code>numRows</code> represent the number
of columns and rows in the corresponding TTY.</p>
<h4><code>writeStream.hasColors([count][, env])</code><span><a class="mark" href="#tty_writestream_hascolors_count_env" id="tty_writestream_hascolors_count_env">#</a></span></h4>
<div class="api_metadata">
<span>Added in: v11.13.0, v10.16.0</span>
</div>
<ul>
<li><code>count</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;integer></a> The number of colors that are requested (minimum 2).
<strong>Default:</strong> 16.</li>
<li><code>env</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> An object containing the environment variables to check. This
enables simulating the usage of a specific terminal. <strong>Default:</strong>
<code>process.env</code>.</li>
<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
</ul>
<p>Returns <code>true</code> if the <code>writeStream</code> supports at least as many colors as provided
in <code>count</code>. Minimum support is 2 (black and white).</p>
<p>This has the same false positives and negatives as described in
<a href="#tty_writestream_getcolordepth_env"><code>writeStream.getColorDepth()</code></a>.</p>
<pre><code class="language-js">process.<span class="hljs-property">stdout</span>.<span class="hljs-title function_">hasColors</span>();
<span class="hljs-comment">// Returns true or false depending on if `stdout` supports at least 16 colors.</span>
process.<span class="hljs-property">stdout</span>.<span class="hljs-title function_">hasColors</span>(<span class="hljs-number">256</span>);
<span class="hljs-comment">// Returns true or false depending on if `stdout` supports at least 256 colors.</span>
process.<span class="hljs-property">stdout</span>.<span class="hljs-title function_">hasColors</span>({ <span class="hljs-attr">TMUX</span>: <span class="hljs-string">'1'</span> });
<span class="hljs-comment">// Returns true.</span>
process.<span class="hljs-property">stdout</span>.<span class="hljs-title function_">hasColors</span>(<span class="hljs-number">2</span> ** <span class="hljs-number">24</span>, { <span class="hljs-attr">TMUX</span>: <span class="hljs-string">'1'</span> });
<span class="hljs-comment">// Returns false (the environment setting pretends to support 2 ** 8 colors).</span></code></pre>
<h4><code>writeStream.isTTY</code><span><a class="mark" href="#tty_writestream_istty" id="tty_writestream_istty">#</a></span></h4>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<p>A <code>boolean</code> that is always <code>true</code>.</p>
<h4><code>writeStream.moveCursor(dx, dy[, callback])</code><span><a class="mark" href="#tty_writestream_movecursor_dx_dy_callback" id="tty_writestream_movecursor_dx_dy_callback">#</a></span></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v12.7.0</td>
<td><p>The stream's write() callback and return value are exposed.</p></td></tr>
<tr><td>v0.7.7</td>
<td><p><span>Added in: v0.7.7</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>dx</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
<li><code>dy</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> Invoked once the operation completes.</li>
<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> <code>false</code> if the stream wishes for the calling code to wait
for the <code>'drain'</code> event to be emitted before continuing to write additional
data; otherwise <code>true</code>.</li>
</ul>
<p><code>writeStream.moveCursor()</code> moves this <code>WriteStream</code>'s cursor <em>relative</em> to its
current position.</p>
<h4><code>writeStream.rows</code><span><a class="mark" href="#tty_writestream_rows" id="tty_writestream_rows">#</a></span></h4>
<div class="api_metadata">
<span>Added in: v0.7.7</span>
</div>
<p>A <code>number</code> specifying the number of rows the TTY currently has. This property
is updated whenever the <code>'resize'</code> event is emitted.</p>
</section><section><h3><code>tty.isatty(fd)</code><span><a class="mark" href="#tty_tty_isatty_fd" id="tty_tty_isatty_fd">#</a></span></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li><code>fd</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> A numeric file descriptor</li>
<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
</ul>
<p>The <code>tty.isatty()</code> method returns <code>true</code> if the given <code>fd</code> is associated with
a TTY and <code>false</code> if it is not, including whenever <code>fd</code> is not a non-negative
integer.</p></section>
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