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<header> 91 <div class="header-container"> 92 <h1>Node.js v14.20.1 documentation</h1> 93 <button class="theme-toggle-btn" id="theme-toggle-btn" title="Toggle dark mode/light mode" aria-label="Toggle dark mode/light mode" hidden> 94 <svg xmlns="http://www.w3.org/2000/svg" class="icon dark-icon" height="24" width="24"> 95 <path fill="none" d="M0 0h24v24H0z" /> 96 <path d="M11.1 12.08c-2.33-4.51-.5-8.48.53-10.07C6.27 2.2 1.98 6.59 1.98 12c0 .14.02.28.02.42.62-.27 1.29-.42 2-.42 1.66 0 3.18.83 4.1 2.15A4.01 4.01 0 0111 18c0 1.52-.87 2.83-2.12 3.51.98.32 2.03.5 3.11.5 3.5 0 6.58-1.8 8.37-4.52-2.36.23-6.98-.97-9.26-5.41z"/> 97 <path d="M7 16h-.18C6.4 14.84 5.3 14 4 14c-1.66 0-3 1.34-3 3s1.34 3 3 3h3c1.1 0 2-.9 2-2s-.9-2-2-2z"/> 98 </svg> 99 <svg xmlns="http://www.w3.org/2000/svg" class="icon light-icon" height="24" width="24"> 100 <path d="M0 0h24v24H0z" fill="none" /> 101 <path d="M6.76 4.84l-1.8-1.79-1.41 1.41 1.79 1.79 1.42-1.41zM4 10.5H1v2h3v-2zm9-9.95h-2V3.5h2V.55zm7.45 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href="https://nodejs.org/docs/latest-v14.x/api/tty.html">14.x <b>LTS</b></a></li> 124<li><a href="https://nodejs.org/docs/latest-v13.x/api/tty.html">13.x</a></li> 125<li><a href="https://nodejs.org/docs/latest-v12.x/api/tty.html">12.x <b>LTS</b></a></li> 126<li><a href="https://nodejs.org/docs/latest-v11.x/api/tty.html">11.x</a></li> 127<li><a href="https://nodejs.org/docs/latest-v10.x/api/tty.html">10.x</a></li> 128<li><a href="https://nodejs.org/docs/latest-v9.x/api/tty.html">9.x</a></li> 129<li><a href="https://nodejs.org/docs/latest-v8.x/api/tty.html">8.x</a></li> 130<li><a href="https://nodejs.org/docs/latest-v7.x/api/tty.html">7.x</a></li> 131<li><a href="https://nodejs.org/docs/latest-v6.x/api/tty.html">6.x</a></li> 132<li><a href="https://nodejs.org/docs/latest-v5.x/api/tty.html">5.x</a></li> 133<li><a href="https://nodejs.org/docs/latest-v4.x/api/tty.html">4.x</a></li> 134<li><a href="https://nodejs.org/docs/latest-v0.12.x/api/tty.html">0.12.x</a></li> 135<li><a href="https://nodejs.org/docs/latest-v0.10.x/api/tty.html">0.10.x</a></li></ol> 136 </li> 137 138 <li class="edit_on_github"><a href="https://github.com/nodejs/node/edit/master/doc/api/tty.md">Edit on GitHub</a></li> 139 </ul> 140 </div> 141 <hr> 142 </header> 143 144 <details id="toc" open><summary>Table of contents</summary><ul> 145<li><span class="stability_2"><a href="#tty_tty">TTY</a></span> 146<ul> 147<li><a href="#tty_class_tty_readstream">Class: <code>tty.ReadStream</code></a> 148<ul> 149<li><a href="#tty_readstream_israw"><code>readStream.isRaw</code></a></li> 150<li><a href="#tty_readstream_istty"><code>readStream.isTTY</code></a></li> 151<li><a href="#tty_readstream_setrawmode_mode"><code>readStream.setRawMode(mode)</code></a></li> 152</ul> 153</li> 154<li><a href="#tty_class_tty_writestream">Class: <code>tty.WriteStream</code></a> 155<ul> 156<li><a href="#tty_event_resize">Event: <code>'resize'</code></a></li> 157<li><a href="#tty_writestream_clearline_dir_callback"><code>writeStream.clearLine(dir[, callback])</code></a></li> 158<li><a href="#tty_writestream_clearscreendown_callback"><code>writeStream.clearScreenDown([callback])</code></a></li> 159<li><a href="#tty_writestream_columns"><code>writeStream.columns</code></a></li> 160<li><a href="#tty_writestream_cursorto_x_y_callback"><code>writeStream.cursorTo(x[, y][, callback])</code></a></li> 161<li><a href="#tty_writestream_getcolordepth_env"><code>writeStream.getColorDepth([env])</code></a></li> 162<li><a href="#tty_writestream_getwindowsize"><code>writeStream.getWindowSize()</code></a></li> 163<li><a href="#tty_writestream_hascolors_count_env"><code>writeStream.hasColors([count][, env])</code></a></li> 164<li><a href="#tty_writestream_istty"><code>writeStream.isTTY</code></a></li> 165<li><a href="#tty_writestream_movecursor_dx_dy_callback"><code>writeStream.moveCursor(dx, dy[, callback])</code></a></li> 166<li><a href="#tty_writestream_rows"><code>writeStream.rows</code></a></li> 167</ul> 168</li> 169<li><a href="#tty_tty_isatty_fd"><code>tty.isatty(fd)</code></a></li> 170</ul> 171</li> 172</ul></details> 173 174 <div id="apicontent"> 175 <h2>TTY<span><a class="mark" href="#tty_tty" id="tty_tty">#</a></span></h2> 176 177<p></p><div class="api_stability api_stability_2"><a href="documentation.html#documentation_stability_index">Stability: 2</a> - Stable</div><p></p> 178<p><strong>Source Code:</strong> <a href="https://github.com/nodejs/node/blob/v14.20.1/lib/tty.js">lib/tty.js</a></p> 179<p>The <code>tty</code> module provides the <code>tty.ReadStream</code> and <code>tty.WriteStream</code> classes. 180In most cases, it will not be necessary or possible to use this module directly. 181However, it can be accessed using:</p> 182<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> 183<p>When Node.js detects that it is being run with a text terminal ("TTY") 184attached, <a href="process.html#process_process_stdin"><code>process.stdin</code></a> will, by default, be initialized as an instance of 185<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 186default, be instances of <code>tty.WriteStream</code>. The preferred method of determining 187whether Node.js is being run within a TTY context is to check that the value of 188the <code>process.stdout.isTTY</code> property is <code>true</code>:</p> 189<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> 190true 191<span class="hljs-meta">$ </span><span class="language-bash">node -p -e <span class="hljs-string">"Boolean(process.stdout.isTTY)"</span> | cat</span> 192false</code></pre> 193<p>In most cases, there should be little to no reason for an application to 194manually create instances of the <code>tty.ReadStream</code> and <code>tty.WriteStream</code> 195classes.</p> 196<section><h3>Class: <code>tty.ReadStream</code><span><a class="mark" href="#tty_class_tty_readstream" id="tty_class_tty_readstream">#</a></span></h3> 197<div class="api_metadata"> 198<span>Added in: v0.5.8</span> 199</div> 200<ul> 201<li>Extends: <a href="net.html#net_class_net_socket" class="type"><net.Socket></a></li> 202</ul> 203<p>Represents the readable side of a TTY. In normal circumstances 204<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 205process and there should be no reason to create additional instances.</p> 206<h4><code>readStream.isRaw</code><span><a class="mark" href="#tty_readstream_israw" id="tty_readstream_israw">#</a></span></h4> 207<div class="api_metadata"> 208<span>Added in: v0.7.7</span> 209</div> 210<p>A <code>boolean</code> that is <code>true</code> if the TTY is currently configured to operate as a 211raw device. Defaults to <code>false</code>.</p> 212<h4><code>readStream.isTTY</code><span><a class="mark" href="#tty_readstream_istty" id="tty_readstream_istty">#</a></span></h4> 213<div class="api_metadata"> 214<span>Added in: v0.5.8</span> 215</div> 216<p>A <code>boolean</code> that is always <code>true</code> for <code>tty.ReadStream</code> instances.</p> 217<h4><code>readStream.setRawMode(mode)</code><span><a class="mark" href="#tty_readstream_setrawmode_mode" id="tty_readstream_setrawmode_mode">#</a></span></h4> 218<div class="api_metadata"> 219<span>Added in: v0.7.7</span> 220</div> 221<ul> 222<li><code>mode</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> If <code>true</code>, configures the <code>tty.ReadStream</code> to operate as a 223raw device. If <code>false</code>, configures the <code>tty.ReadStream</code> to operate in its 224default mode. The <code>readStream.isRaw</code> property will be set to the resulting 225mode.</li> 226<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this" class="type"><this></a> The read stream instance.</li> 227</ul> 228<p>Allows configuration of <code>tty.ReadStream</code> so that it operates as a raw device.</p> 229<p>When in raw mode, input is always available character-by-character, not 230including modifiers. Additionally, all special processing of characters by the 231terminal is disabled, including echoing input characters. 232<kbd>Ctrl</kbd>+<kbd>C</kbd> will no longer cause a <code>SIGINT</code> when in this mode.</p> 233</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> 234<div class="api_metadata"> 235<span>Added in: v0.5.8</span> 236</div> 237<ul> 238<li>Extends: <a href="net.html#net_class_net_socket" class="type"><net.Socket></a></li> 239</ul> 240<p>Represents the writable side of a TTY. In normal circumstances, 241<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 242<code>tty.WriteStream</code> instances created for a Node.js process and there 243should be no reason to create additional instances.</p> 244<h4>Event: <code>'resize'</code><span><a class="mark" href="#tty_event_resize" id="tty_event_resize">#</a></span></h4> 245<div class="api_metadata"> 246<span>Added in: v0.7.7</span> 247</div> 248<p>The <code>'resize'</code> event is emitted whenever either of the <code>writeStream.columns</code> 249or <code>writeStream.rows</code> properties have changed. No arguments are passed to the 250listener callback when called.</p> 251<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> { 252 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'screen size has changed!'</span>); 253 <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>); 254});</code></pre> 255<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> 256<div class="api_metadata"> 257<details class="changelog"><summary>History</summary> 258<table> 259<tbody><tr><th>Version</th><th>Changes</th></tr> 260<tr><td>v12.7.0</td> 261<td><p>The stream's write() callback and return value are exposed.</p></td></tr> 262<tr><td>v0.7.7</td> 263<td><p><span>Added in: v0.7.7</span></p></td></tr> 264</tbody></table> 265</details> 266</div> 267<ul> 268<li><code>dir</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> 269<ul> 270<li><code>-1</code>: to the left from cursor</li> 271<li><code>1</code>: to the right from cursor</li> 272<li><code>0</code>: the entire line</li> 273</ul> 274</li> 275<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Invoked once the operation completes.</li> 276<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> <code>false</code> if the stream wishes for the calling code to wait 277for the <code>'drain'</code> event to be emitted before continuing to write additional 278data; otherwise <code>true</code>.</li> 279</ul> 280<p><code>writeStream.clearLine()</code> clears the current line of this <code>WriteStream</code> in a 281direction identified by <code>dir</code>.</p> 282<h4><code>writeStream.clearScreenDown([callback])</code><span><a class="mark" href="#tty_writestream_clearscreendown_callback" id="tty_writestream_clearscreendown_callback">#</a></span></h4> 283<div class="api_metadata"> 284<details class="changelog"><summary>History</summary> 285<table> 286<tbody><tr><th>Version</th><th>Changes</th></tr> 287<tr><td>v12.7.0</td> 288<td><p>The stream's write() callback and return value are exposed.</p></td></tr> 289<tr><td>v0.7.7</td> 290<td><p><span>Added in: v0.7.7</span></p></td></tr> 291</tbody></table> 292</details> 293</div> 294<ul> 295<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Invoked once the operation completes.</li> 296<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> <code>false</code> if the stream wishes for the calling code to wait 297for the <code>'drain'</code> event to be emitted before continuing to write additional 298data; otherwise <code>true</code>.</li> 299</ul> 300<p><code>writeStream.clearScreenDown()</code> clears this <code>WriteStream</code> from the current 301cursor down.</p> 302<h4><code>writeStream.columns</code><span><a class="mark" href="#tty_writestream_columns" id="tty_writestream_columns">#</a></span></h4> 303<div class="api_metadata"> 304<span>Added in: v0.7.7</span> 305</div> 306<p>A <code>number</code> specifying the number of columns the TTY currently has. This property 307is updated whenever the <code>'resize'</code> event is emitted.</p> 308<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> 309<div class="api_metadata"> 310<details class="changelog"><summary>History</summary> 311<table> 312<tbody><tr><th>Version</th><th>Changes</th></tr> 313<tr><td>v12.7.0</td> 314<td><p>The stream's write() callback and return value are exposed.</p></td></tr> 315<tr><td>v0.7.7</td> 316<td><p><span>Added in: v0.7.7</span></p></td></tr> 317</tbody></table> 318</details> 319</div> 320<ul> 321<li><code>x</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 322<li><code>y</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 323<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Invoked once the operation completes.</li> 324<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> <code>false</code> if the stream wishes for the calling code to wait 325for the <code>'drain'</code> event to be emitted before continuing to write additional 326data; otherwise <code>true</code>.</li> 327</ul> 328<p><code>writeStream.cursorTo()</code> moves this <code>WriteStream</code>'s cursor to the specified 329position.</p> 330<h4><code>writeStream.getColorDepth([env])</code><span><a class="mark" href="#tty_writestream_getcolordepth_env" id="tty_writestream_getcolordepth_env">#</a></span></h4> 331<div class="api_metadata"> 332<span>Added in: v9.9.0</span> 333</div> 334<ul> 335<li><code>env</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> An object containing the environment variables to check. This 336enables simulating the usage of a specific terminal. <strong>Default:</strong> 337<code>process.env</code>.</li> 338<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 339</ul> 340<p>Returns:</p> 341<ul> 342<li><code>1</code> for 2,</li> 343<li><code>4</code> for 16,</li> 344<li><code>8</code> for 256,</li> 345<li><code>24</code> for 16,777,216</li> 346</ul> 347<p>colors supported.</p> 348<p>Use this to determine what colors the terminal supports. Due to the nature of 349colors in terminals it is possible to either have false positives or false 350negatives. It depends on process information and the environment variables that 351may lie about what terminal is used. 352It is possible to pass in an <code>env</code> object to simulate the usage of a specific 353terminal. This can be useful to check how specific environment settings behave.</p> 354<p>To enforce a specific color support, use one of the below environment settings.</p> 355<ul> 356<li>2 colors: <code>FORCE_COLOR = 0</code> (Disables colors)</li> 357<li>16 colors: <code>FORCE_COLOR = 1</code></li> 358<li>256 colors: <code>FORCE_COLOR = 2</code></li> 359<li>16,777,216 colors: <code>FORCE_COLOR = 3</code></li> 360</ul> 361<p>Disabling color support is also possible by using the <code>NO_COLOR</code> and 362<code>NODE_DISABLE_COLORS</code> environment variables.</p> 363<h4><code>writeStream.getWindowSize()</code><span><a class="mark" href="#tty_writestream_getwindowsize" id="tty_writestream_getwindowsize">#</a></span></h4> 364<div class="api_metadata"> 365<span>Added in: v0.7.7</span> 366</div> 367<ul> 368<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number[]></a></li> 369</ul> 370<p><code>writeStream.getWindowSize()</code> returns the size of the TTY 371corresponding to this <code>WriteStream</code>. The array is of the type 372<code>[numColumns, numRows]</code> where <code>numColumns</code> and <code>numRows</code> represent the number 373of columns and rows in the corresponding TTY.</p> 374<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> 375<div class="api_metadata"> 376<span>Added in: v11.13.0, v10.16.0</span> 377</div> 378<ul> 379<li><code>count</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> The number of colors that are requested (minimum 2). 380<strong>Default:</strong> 16.</li> 381<li><code>env</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> An object containing the environment variables to check. This 382enables simulating the usage of a specific terminal. <strong>Default:</strong> 383<code>process.env</code>.</li> 384<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 385</ul> 386<p>Returns <code>true</code> if the <code>writeStream</code> supports at least as many colors as provided 387in <code>count</code>. Minimum support is 2 (black and white).</p> 388<p>This has the same false positives and negatives as described in 389<a href="#tty_writestream_getcolordepth_env"><code>writeStream.getColorDepth()</code></a>.</p> 390<pre><code class="language-js">process.<span class="hljs-property">stdout</span>.<span class="hljs-title function_">hasColors</span>(); 391<span class="hljs-comment">// Returns true or false depending on if `stdout` supports at least 16 colors.</span> 392process.<span class="hljs-property">stdout</span>.<span class="hljs-title function_">hasColors</span>(<span class="hljs-number">256</span>); 393<span class="hljs-comment">// Returns true or false depending on if `stdout` supports at least 256 colors.</span> 394process.<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> }); 395<span class="hljs-comment">// Returns true.</span> 396process.<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> }); 397<span class="hljs-comment">// Returns false (the environment setting pretends to support 2 ** 8 colors).</span></code></pre> 398<h4><code>writeStream.isTTY</code><span><a class="mark" href="#tty_writestream_istty" id="tty_writestream_istty">#</a></span></h4> 399<div class="api_metadata"> 400<span>Added in: v0.5.8</span> 401</div> 402<p>A <code>boolean</code> that is always <code>true</code>.</p> 403<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> 404<div class="api_metadata"> 405<details class="changelog"><summary>History</summary> 406<table> 407<tbody><tr><th>Version</th><th>Changes</th></tr> 408<tr><td>v12.7.0</td> 409<td><p>The stream's write() callback and return value are exposed.</p></td></tr> 410<tr><td>v0.7.7</td> 411<td><p><span>Added in: v0.7.7</span></p></td></tr> 412</tbody></table> 413</details> 414</div> 415<ul> 416<li><code>dx</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 417<li><code>dy</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 418<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Invoked once the operation completes.</li> 419<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> <code>false</code> if the stream wishes for the calling code to wait 420for the <code>'drain'</code> event to be emitted before continuing to write additional 421data; otherwise <code>true</code>.</li> 422</ul> 423<p><code>writeStream.moveCursor()</code> moves this <code>WriteStream</code>'s cursor <em>relative</em> to its 424current position.</p> 425<h4><code>writeStream.rows</code><span><a class="mark" href="#tty_writestream_rows" id="tty_writestream_rows">#</a></span></h4> 426<div class="api_metadata"> 427<span>Added in: v0.7.7</span> 428</div> 429<p>A <code>number</code> specifying the number of rows the TTY currently has. This property 430is updated whenever the <code>'resize'</code> event is emitted.</p> 431</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> 432<div class="api_metadata"> 433<span>Added in: v0.5.8</span> 434</div> 435<ul> 436<li><code>fd</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> A numeric file descriptor</li> 437<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 438</ul> 439<p>The <code>tty.isatty()</code> method returns <code>true</code> if the given <code>fd</code> is associated with 440a TTY and <code>false</code> if it is not, including whenever <code>fd</code> is not a non-negative 441integer.</p></section> 442 <!-- API END --> 443 </div> 444 </div> 445 </div> 446 <script> 447 'use strict'; 448 { 449 const kCustomPreference = 'customDarkTheme'; 450 const userSettings = sessionStorage.getItem(kCustomPreference); 451 const themeToggleButton = document.getElementById('theme-toggle-btn'); 452 if (userSettings === null && window.matchMedia) { 453 const mq = window.matchMedia('(prefers-color-scheme: dark)'); 454 if ('onchange' in mq) { 455 function mqChangeListener(e) { 456 document.body.classList.toggle('dark-mode', e.matches); 457 } 458 mq.addEventListener('change', mqChangeListener); 459 if (themeToggleButton) { 460 themeToggleButton.addEventListener('click', function() { 461 mq.removeEventListener('change', mqChangeListener); 462 }, { once: true }); 463 } 464 } 465 if (mq.matches) { 466 document.body.classList.add('dark-mode'); 467 } 468 } else if (userSettings === 'true') { 469 document.body.classList.add('dark-mode'); 470 } 471 if (themeToggleButton) { 472 themeToggleButton.hidden = false; 473 themeToggleButton.addEventListener('click', function() { 474 sessionStorage.setItem( 475 kCustomPreference, 476 document.body.classList.toggle('dark-mode') 477 ); 478 }); 479 } 480 } 481 </script> 482</body> 483</html> 484