1<!DOCTYPE html> 2<html lang="en"> 3<head> 4 <meta charset="utf-8"> 5 <meta name="viewport" content="width=device-width"> 6 <meta name="nodejs.org:node-version" content="v18.18.2"> 7 <title>Console | Node.js v18.18.2 Documentation</title> 8 <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Lato:400,700,400italic&display=fallback"> 9 <link rel="stylesheet" href="assets/style.css"> 10 <link rel="stylesheet" href="assets/hljs.css"> 11 <link rel="canonical" href="https://nodejs.org/api/console.html"> 12 <script async defer src="assets/api.js" type="text/javascript"></script> 13 14</head> 15<body class="alt apidoc" id="api-section-console"> 16 <div id="content" class="clearfix"> 17 <div id="column2" class="interior"> 18 <div id="intro" class="interior"> 19 <a href="/" title="Go back to the home page"> 20 Node.js 21 </a> 22 </div> 23 <ul> 24<li><a href="documentation.html" class="nav-documentation">About this documentation</a></li> 25<li><a href="synopsis.html" 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85<li><a href="webcrypto.html" class="nav-webcrypto">Web Crypto API</a></li> 86<li><a href="webstreams.html" class="nav-webstreams">Web Streams API</a></li> 87<li><a href="worker_threads.html" class="nav-worker_threads">Worker threads</a></li> 88<li><a href="zlib.html" class="nav-zlib">Zlib</a></li> 89</ul> 90<hr class="line"> 91<ul> 92<li><a href="https://github.com/nodejs/node" class="nav-https-github-com-nodejs-node">Code repository and issue tracker</a></li> 93</ul> 94 </div> 95 96 <div id="column1" data-id="console" class="interior"> 97 <header class="header"> 98 <div class="header-container"> 99 <h1>Node.js v18.18.2 documentation</h1> 100 <button class="theme-toggle-btn" id="theme-toggle-btn" title="Toggle dark mode/light mode" aria-label="Toggle dark mode/light mode" hidden> 101 <svg xmlns="http://www.w3.org/2000/svg" class="icon dark-icon" height="24" width="24"> 102 <path fill="none" d="M0 0h24v24H0z" /> 103 <path d="M11.1 12.08c-2.33-4.51-.5-8.48.53-10.07C6.27 2.2 1.98 6.59 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class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 119 Table of contents 120 </a> 121 122 <div class="picker"><div class="toc"><ul> 123<li><span class="stability_2"><a href="#console">Console</a></span> 124<ul> 125<li><a href="#class-console">Class: <code>Console</code></a> 126<ul> 127<li><a href="#new-consolestdout-stderr-ignoreerrors"><code>new Console(stdout[, stderr][, ignoreErrors])</code></a></li> 128<li><a href="#new-consoleoptions"><code>new Console(options)</code></a></li> 129<li><a href="#consoleassertvalue-message"><code>console.assert(value[, ...message])</code></a></li> 130<li><a href="#consoleclear"><code>console.clear()</code></a></li> 131<li><a href="#consolecountlabel"><code>console.count([label])</code></a></li> 132<li><a href="#consolecountresetlabel"><code>console.countReset([label])</code></a></li> 133<li><a href="#consoledebugdata-args"><code>console.debug(data[, ...args])</code></a></li> 134<li><a href="#consoledirobj-options"><code>console.dir(obj[, options])</code></a></li> 135<li><a href="#consoledirxmldata"><code>console.dirxml(...data)</code></a></li> 136<li><a href="#consoleerrordata-args"><code>console.error([data][, ...args])</code></a></li> 137<li><a href="#consolegrouplabel"><code>console.group([...label])</code></a></li> 138<li><a href="#consolegroupcollapsed"><code>console.groupCollapsed()</code></a></li> 139<li><a href="#consolegroupend"><code>console.groupEnd()</code></a></li> 140<li><a href="#consoleinfodata-args"><code>console.info([data][, ...args])</code></a></li> 141<li><a href="#consolelogdata-args"><code>console.log([data][, ...args])</code></a></li> 142<li><a href="#consoletabletabulardata-properties"><code>console.table(tabularData[, properties])</code></a></li> 143<li><a href="#consoletimelabel"><code>console.time([label])</code></a></li> 144<li><a href="#consoletimeendlabel"><code>console.timeEnd([label])</code></a></li> 145<li><a href="#consoletimeloglabel-data"><code>console.timeLog([label][, ...data])</code></a></li> 146<li><a href="#consoletracemessage-args"><code>console.trace([message][, ...args])</code></a></li> 147<li><a href="#consolewarndata-args"><code>console.warn([data][, ...args])</code></a></li> 148</ul> 149</li> 150<li><a href="#inspector-only-methods">Inspector only methods</a> 151<ul> 152<li><a href="#consoleprofilelabel"><code>console.profile([label])</code></a></li> 153<li><a href="#consoleprofileendlabel"><code>console.profileEnd([label])</code></a></li> 154<li><a href="#consoletimestamplabel"><code>console.timeStamp([label])</code></a></li> 155</ul> 156</li> 157</ul> 158</li> 159</ul></div></div> 160 </li> 161 162 163 <li class="picker-header"> 164 <a href="#"> 165 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 166 Index 167 </a> 168 169 <div class="picker"><ul> 170<li><a href="documentation.html" class="nav-documentation">About this documentation</a></li> 171<li><a href="synopsis.html" class="nav-synopsis">Usage and example</a></li> 172 173 <li> 174 <a href="index.html">Index</a> 175 </li> 176 </ul> 177 178<hr class="line"> 179<ul> 180<li><a href="assert.html" class="nav-assert">Assertion testing</a></li> 181<li><a href="async_context.html" class="nav-async_context">Asynchronous context tracking</a></li> 182<li><a href="async_hooks.html" class="nav-async_hooks">Async hooks</a></li> 183<li><a href="buffer.html" class="nav-buffer">Buffer</a></li> 184<li><a href="addons.html" class="nav-addons">C++ addons</a></li> 185<li><a href="n-api.html" class="nav-n-api">C/C++ addons with Node-API</a></li> 186<li><a href="embedding.html" class="nav-embedding">C++ embedder API</a></li> 187<li><a href="child_process.html" class="nav-child_process">Child processes</a></li> 188<li><a href="cluster.html" class="nav-cluster">Cluster</a></li> 189<li><a href="cli.html" class="nav-cli">Command-line options</a></li> 190<li><a href="console.html" class="nav-console active">Console</a></li> 191<li><a href="corepack.html" class="nav-corepack">Corepack</a></li> 192<li><a href="crypto.html" class="nav-crypto">Crypto</a></li> 193<li><a href="debugger.html" class="nav-debugger">Debugger</a></li> 194<li><a href="deprecations.html" class="nav-deprecations">Deprecated APIs</a></li> 195<li><a href="diagnostics_channel.html" class="nav-diagnostics_channel">Diagnostics Channel</a></li> 196<li><a href="dns.html" class="nav-dns">DNS</a></li> 197<li><a href="domain.html" class="nav-domain">Domain</a></li> 198<li><a href="errors.html" class="nav-errors">Errors</a></li> 199<li><a href="events.html" class="nav-events">Events</a></li> 200<li><a href="fs.html" class="nav-fs">File system</a></li> 201<li><a href="globals.html" class="nav-globals">Globals</a></li> 202<li><a href="http.html" class="nav-http">HTTP</a></li> 203<li><a href="http2.html" class="nav-http2">HTTP/2</a></li> 204<li><a href="https.html" class="nav-https">HTTPS</a></li> 205<li><a href="inspector.html" class="nav-inspector">Inspector</a></li> 206<li><a href="intl.html" class="nav-intl">Internationalization</a></li> 207<li><a href="modules.html" class="nav-modules">Modules: CommonJS modules</a></li> 208<li><a href="esm.html" class="nav-esm">Modules: ECMAScript modules</a></li> 209<li><a href="module.html" class="nav-module">Modules: <code>node:module</code> API</a></li> 210<li><a href="packages.html" class="nav-packages">Modules: Packages</a></li> 211<li><a href="net.html" class="nav-net">Net</a></li> 212<li><a href="os.html" class="nav-os">OS</a></li> 213<li><a href="path.html" class="nav-path">Path</a></li> 214<li><a href="perf_hooks.html" class="nav-perf_hooks">Performance hooks</a></li> 215<li><a href="permissions.html" class="nav-permissions">Permissions</a></li> 216<li><a href="process.html" class="nav-process">Process</a></li> 217<li><a href="punycode.html" class="nav-punycode">Punycode</a></li> 218<li><a href="querystring.html" class="nav-querystring">Query strings</a></li> 219<li><a href="readline.html" class="nav-readline">Readline</a></li> 220<li><a href="repl.html" class="nav-repl">REPL</a></li> 221<li><a href="report.html" class="nav-report">Report</a></li> 222<li><a href="single-executable-applications.html" class="nav-single-executable-applications">Single executable applications</a></li> 223<li><a href="stream.html" class="nav-stream">Stream</a></li> 224<li><a href="string_decoder.html" class="nav-string_decoder">String decoder</a></li> 225<li><a href="test.html" class="nav-test">Test runner</a></li> 226<li><a href="timers.html" class="nav-timers">Timers</a></li> 227<li><a href="tls.html" class="nav-tls">TLS/SSL</a></li> 228<li><a href="tracing.html" class="nav-tracing">Trace events</a></li> 229<li><a href="tty.html" class="nav-tty">TTY</a></li> 230<li><a href="dgram.html" class="nav-dgram">UDP/datagram</a></li> 231<li><a href="url.html" class="nav-url">URL</a></li> 232<li><a href="util.html" class="nav-util">Utilities</a></li> 233<li><a href="v8.html" class="nav-v8">V8</a></li> 234<li><a href="vm.html" class="nav-vm">VM</a></li> 235<li><a href="wasi.html" class="nav-wasi">WASI</a></li> 236<li><a href="webcrypto.html" class="nav-webcrypto">Web Crypto API</a></li> 237<li><a href="webstreams.html" class="nav-webstreams">Web Streams API</a></li> 238<li><a href="worker_threads.html" class="nav-worker_threads">Worker threads</a></li> 239<li><a href="zlib.html" class="nav-zlib">Zlib</a></li> 240</ul> 241<hr class="line"> 242<ul> 243<li><a href="https://github.com/nodejs/node" class="nav-https-github-com-nodejs-node">Code repository and issue tracker</a></li> 244</ul></div> 245 </li> 246 247 248 <li class="picker-header"> 249 <a href="#"> 250 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 251 Other versions 252 </a> 253 <div class="picker"><ol id="alt-docs"><li><a href="https://nodejs.org/docs/latest-v20.x/api/console.html">20.x</a></li> 254<li><a href="https://nodejs.org/docs/latest-v19.x/api/console.html">19.x</a></li> 255<li><a href="https://nodejs.org/docs/latest-v18.x/api/console.html">18.x <b>LTS</b></a></li> 256<li><a href="https://nodejs.org/docs/latest-v17.x/api/console.html">17.x</a></li> 257<li><a href="https://nodejs.org/docs/latest-v16.x/api/console.html">16.x</a></li> 258<li><a href="https://nodejs.org/docs/latest-v15.x/api/console.html">15.x</a></li> 259<li><a href="https://nodejs.org/docs/latest-v14.x/api/console.html">14.x</a></li> 260<li><a href="https://nodejs.org/docs/latest-v13.x/api/console.html">13.x</a></li> 261<li><a href="https://nodejs.org/docs/latest-v12.x/api/console.html">12.x</a></li> 262<li><a href="https://nodejs.org/docs/latest-v11.x/api/console.html">11.x</a></li> 263<li><a href="https://nodejs.org/docs/latest-v10.x/api/console.html">10.x</a></li> 264<li><a href="https://nodejs.org/docs/latest-v9.x/api/console.html">9.x</a></li> 265<li><a href="https://nodejs.org/docs/latest-v8.x/api/console.html">8.x</a></li> 266<li><a href="https://nodejs.org/docs/latest-v7.x/api/console.html">7.x</a></li> 267<li><a href="https://nodejs.org/docs/latest-v6.x/api/console.html">6.x</a></li> 268<li><a href="https://nodejs.org/docs/latest-v5.x/api/console.html">5.x</a></li> 269<li><a href="https://nodejs.org/docs/latest-v4.x/api/console.html">4.x</a></li> 270<li><a href="https://nodejs.org/docs/latest-v0.12.x/api/console.html">0.12.x</a></li> 271<li><a href="https://nodejs.org/docs/latest-v0.10.x/api/console.html">0.10.x</a></li></ol></div> 272 </li> 273 274 <li class="picker-header"> 275 <a href="#"> 276 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 277 Options 278 </a> 279 280 <div class="picker"> 281 <ul> 282 <li> 283 <a href="all.html">View on single page</a> 284 </li> 285 <li> 286 <a href="console.json">View as JSON</a> 287 </li> 288 <li class="edit_on_github"><a href="https://github.com/nodejs/node/edit/main/doc/api/console.md">Edit on GitHub</a></li> 289 </ul> 290 </div> 291 </li> 292 </ul> 293 </div> 294 <hr> 295 </header> 296 297 <details id="toc" open><summary>Table of contents</summary><ul> 298<li><span class="stability_2"><a href="#console">Console</a></span> 299<ul> 300<li><a href="#class-console">Class: <code>Console</code></a> 301<ul> 302<li><a href="#new-consolestdout-stderr-ignoreerrors"><code>new Console(stdout[, stderr][, ignoreErrors])</code></a></li> 303<li><a href="#new-consoleoptions"><code>new Console(options)</code></a></li> 304<li><a href="#consoleassertvalue-message"><code>console.assert(value[, ...message])</code></a></li> 305<li><a href="#consoleclear"><code>console.clear()</code></a></li> 306<li><a href="#consolecountlabel"><code>console.count([label])</code></a></li> 307<li><a href="#consolecountresetlabel"><code>console.countReset([label])</code></a></li> 308<li><a href="#consoledebugdata-args"><code>console.debug(data[, ...args])</code></a></li> 309<li><a href="#consoledirobj-options"><code>console.dir(obj[, options])</code></a></li> 310<li><a href="#consoledirxmldata"><code>console.dirxml(...data)</code></a></li> 311<li><a href="#consoleerrordata-args"><code>console.error([data][, ...args])</code></a></li> 312<li><a href="#consolegrouplabel"><code>console.group([...label])</code></a></li> 313<li><a href="#consolegroupcollapsed"><code>console.groupCollapsed()</code></a></li> 314<li><a href="#consolegroupend"><code>console.groupEnd()</code></a></li> 315<li><a href="#consoleinfodata-args"><code>console.info([data][, ...args])</code></a></li> 316<li><a href="#consolelogdata-args"><code>console.log([data][, ...args])</code></a></li> 317<li><a href="#consoletabletabulardata-properties"><code>console.table(tabularData[, properties])</code></a></li> 318<li><a href="#consoletimelabel"><code>console.time([label])</code></a></li> 319<li><a href="#consoletimeendlabel"><code>console.timeEnd([label])</code></a></li> 320<li><a href="#consoletimeloglabel-data"><code>console.timeLog([label][, ...data])</code></a></li> 321<li><a href="#consoletracemessage-args"><code>console.trace([message][, ...args])</code></a></li> 322<li><a href="#consolewarndata-args"><code>console.warn([data][, ...args])</code></a></li> 323</ul> 324</li> 325<li><a href="#inspector-only-methods">Inspector only methods</a> 326<ul> 327<li><a href="#consoleprofilelabel"><code>console.profile([label])</code></a></li> 328<li><a href="#consoleprofileendlabel"><code>console.profileEnd([label])</code></a></li> 329<li><a href="#consoletimestamplabel"><code>console.timeStamp([label])</code></a></li> 330</ul> 331</li> 332</ul> 333</li> 334</ul></details> 335 336 <div id="apicontent"> 337 <h2>Console<span><a class="mark" href="#console" id="console">#</a></span><a aria-hidden="true" class="legacy" id="console_console"></a></h2> 338 339<p></p><div class="api_stability api_stability_2"><a href="documentation.html#stability-index">Stability: 2</a> - Stable</div><p></p> 340<p><strong>Source Code:</strong> <a href="https://github.com/nodejs/node/blob/v18.18.2/lib/console.js">lib/console.js</a></p> 341<p>The <code>node:console</code> module provides a simple debugging console that is similar to 342the JavaScript console mechanism provided by web browsers.</p> 343<p>The module exports two specific components:</p> 344<ul> 345<li>A <code>Console</code> class with methods such as <code>console.log()</code>, <code>console.error()</code>, and 346<code>console.warn()</code> that can be used to write to any Node.js stream.</li> 347<li>A global <code>console</code> instance configured to write to <a href="process.html#processstdout"><code>process.stdout</code></a> and 348<a href="process.html#processstderr"><code>process.stderr</code></a>. The global <code>console</code> can be used without calling 349<code>require('node:console')</code>.</li> 350</ul> 351<p><em><strong>Warning</strong></em>: The global console object's methods are neither consistently 352synchronous like the browser APIs they resemble, nor are they consistently 353asynchronous like all other Node.js streams. See the <a href="process.html#a-note-on-process-io">note on process I/O</a> for 354more information.</p> 355<p>Example using the global <code>console</code>:</p> 356<pre><code class="language-js"><span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'hello world'</span>); 357<span class="hljs-comment">// Prints: hello world, to stdout</span> 358<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'hello %s'</span>, <span class="hljs-string">'world'</span>); 359<span class="hljs-comment">// Prints: hello world, to stdout</span> 360<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-keyword">new</span> <span class="hljs-title class_">Error</span>(<span class="hljs-string">'Whoops, something bad happened'</span>)); 361<span class="hljs-comment">// Prints error message and stack trace to stderr:</span> 362<span class="hljs-comment">// Error: Whoops, something bad happened</span> 363<span class="hljs-comment">// at [eval]:5:15</span> 364<span class="hljs-comment">// at Script.runInThisContext (node:vm:132:18)</span> 365<span class="hljs-comment">// at Object.runInThisContext (node:vm:309:38)</span> 366<span class="hljs-comment">// at node:internal/process/execution:77:19</span> 367<span class="hljs-comment">// at [eval]-wrapper:6:22</span> 368<span class="hljs-comment">// at evalScript (node:internal/process/execution:76:60)</span> 369<span class="hljs-comment">// at node:internal/main/eval_string:23:3</span> 370 371<span class="hljs-keyword">const</span> name = <span class="hljs-string">'Will Robinson'</span>; 372<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">warn</span>(<span class="hljs-string">`Danger <span class="hljs-subst">${name}</span>! Danger!`</span>); 373<span class="hljs-comment">// Prints: Danger Will Robinson! Danger!, to stderr</span></code> <button class="copy-button">copy</button></pre> 374<p>Example using the <code>Console</code> class:</p> 375<pre><code class="language-js"><span class="hljs-keyword">const</span> out = <span class="hljs-title function_">getStreamSomehow</span>(); 376<span class="hljs-keyword">const</span> err = <span class="hljs-title function_">getStreamSomehow</span>(); 377<span class="hljs-keyword">const</span> myConsole = <span class="hljs-keyword">new</span> <span class="hljs-variable language_">console</span>.<span class="hljs-title class_">Console</span>(out, err); 378 379myConsole.<span class="hljs-title function_">log</span>(<span class="hljs-string">'hello world'</span>); 380<span class="hljs-comment">// Prints: hello world, to out</span> 381myConsole.<span class="hljs-title function_">log</span>(<span class="hljs-string">'hello %s'</span>, <span class="hljs-string">'world'</span>); 382<span class="hljs-comment">// Prints: hello world, to out</span> 383myConsole.<span class="hljs-title function_">error</span>(<span class="hljs-keyword">new</span> <span class="hljs-title class_">Error</span>(<span class="hljs-string">'Whoops, something bad happened'</span>)); 384<span class="hljs-comment">// Prints: [Error: Whoops, something bad happened], to err</span> 385 386<span class="hljs-keyword">const</span> name = <span class="hljs-string">'Will Robinson'</span>; 387myConsole.<span class="hljs-title function_">warn</span>(<span class="hljs-string">`Danger <span class="hljs-subst">${name}</span>! Danger!`</span>); 388<span class="hljs-comment">// Prints: Danger Will Robinson! Danger!, to err</span></code> <button class="copy-button">copy</button></pre> 389<section><h3>Class: <code>Console</code><span><a class="mark" href="#class-console" id="class-console">#</a></span><a aria-hidden="true" class="legacy" id="console_class_console"></a></h3> 390<div class="api_metadata"> 391<details class="changelog"><summary>History</summary> 392<table> 393<tbody><tr><th>Version</th><th>Changes</th></tr> 394<tr><td>v8.0.0</td> 395<td><p>Errors that occur while writing to the underlying streams will now be ignored by default.</p></td></tr> 396</tbody></table> 397</details> 398</div> 399 400<p>The <code>Console</code> class can be used to create a simple logger with configurable 401output streams and can be accessed using either <code>require('node:console').Console</code> 402or <code>console.Console</code> (or their destructured counterparts):</p> 403<pre><code class="language-js"><span class="hljs-keyword">const</span> { <span class="hljs-title class_">Console</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:console'</span>);</code> <button class="copy-button">copy</button></pre> 404<pre><code class="language-js"><span class="hljs-keyword">const</span> { <span class="hljs-title class_">Console</span> } = <span class="hljs-variable language_">console</span>;</code> <button class="copy-button">copy</button></pre> 405<h4><code>new Console(stdout[, stderr][, ignoreErrors])</code><span><a class="mark" href="#new-consolestdout-stderr-ignoreerrors" id="new-consolestdout-stderr-ignoreerrors">#</a></span><a aria-hidden="true" class="legacy" id="console_new_console_stdout_stderr_ignoreerrors"></a></h4> 406<h4><code>new Console(options)</code><span><a class="mark" href="#new-consoleoptions" id="new-consoleoptions">#</a></span><a aria-hidden="true" class="legacy" id="console_new_console_options"></a></h4> 407<div class="api_metadata"> 408<details class="changelog"><summary>History</summary> 409<table> 410<tbody><tr><th>Version</th><th>Changes</th></tr> 411<tr><td>v14.2.0, v12.17.0</td> 412<td><p>The <code>groupIndentation</code> option was introduced.</p></td></tr> 413<tr><td>v11.7.0</td> 414<td><p>The <code>inspectOptions</code> option is introduced.</p></td></tr> 415<tr><td>v10.0.0</td> 416<td><p>The <code>Console</code> constructor now supports an <code>options</code> argument, and the <code>colorMode</code> option was introduced.</p></td></tr> 417<tr><td>v8.0.0</td> 418<td><p>The <code>ignoreErrors</code> option was introduced.</p></td></tr> 419</tbody></table> 420</details> 421</div> 422<ul> 423<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 424<ul> 425<li><code>stdout</code> <a href="stream.html#class-streamwritable" class="type"><stream.Writable></a></li> 426<li><code>stderr</code> <a href="stream.html#class-streamwritable" class="type"><stream.Writable></a></li> 427<li><code>ignoreErrors</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> Ignore errors when writing to the underlying 428streams. <strong>Default:</strong> <code>true</code>.</li> 429<li><code>colorMode</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Set color support for this <code>Console</code> instance. 430Setting to <code>true</code> enables coloring while inspecting values. Setting to 431<code>false</code> disables coloring while inspecting values. Setting to 432<code>'auto'</code> makes color support depend on the value of the <code>isTTY</code> property 433and the value returned by <code>getColorDepth()</code> on the respective stream. This 434option can not be used, if <code>inspectOptions.colors</code> is set as well. 435<strong>Default:</strong> <code>'auto'</code>.</li> 436<li><code>inspectOptions</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> Specifies options that are passed along to 437<a href="util.html#utilinspectobject-options"><code>util.inspect()</code></a>.</li> 438<li><code>groupIndentation</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Set group indentation. 439<strong>Default:</strong> <code>2</code>.</li> 440</ul> 441</li> 442</ul> 443<p>Creates a new <code>Console</code> with one or two writable stream instances. <code>stdout</code> is a 444writable stream to print log or info output. <code>stderr</code> is used for warning or 445error output. If <code>stderr</code> is not provided, <code>stdout</code> is used for <code>stderr</code>.</p> 446<pre><code class="language-js"><span class="hljs-keyword">const</span> output = fs.<span class="hljs-title function_">createWriteStream</span>(<span class="hljs-string">'./stdout.log'</span>); 447<span class="hljs-keyword">const</span> errorOutput = fs.<span class="hljs-title function_">createWriteStream</span>(<span class="hljs-string">'./stderr.log'</span>); 448<span class="hljs-comment">// Custom simple logger</span> 449<span class="hljs-keyword">const</span> logger = <span class="hljs-keyword">new</span> <span class="hljs-title class_">Console</span>({ <span class="hljs-attr">stdout</span>: output, <span class="hljs-attr">stderr</span>: errorOutput }); 450<span class="hljs-comment">// use it like console</span> 451<span class="hljs-keyword">const</span> count = <span class="hljs-number">5</span>; 452logger.<span class="hljs-title function_">log</span>(<span class="hljs-string">'count: %d'</span>, count); 453<span class="hljs-comment">// In stdout.log: count 5</span></code> <button class="copy-button">copy</button></pre> 454<p>The global <code>console</code> is a special <code>Console</code> whose output is sent to 455<a href="process.html#processstdout"><code>process.stdout</code></a> and <a href="process.html#processstderr"><code>process.stderr</code></a>. It is equivalent to calling:</p> 456<pre><code class="language-js"><span class="hljs-keyword">new</span> <span class="hljs-title class_">Console</span>({ <span class="hljs-attr">stdout</span>: process.<span class="hljs-property">stdout</span>, <span class="hljs-attr">stderr</span>: process.<span class="hljs-property">stderr</span> });</code> <button class="copy-button">copy</button></pre> 457<h4><code>console.assert(value[, ...message])</code><span><a class="mark" href="#consoleassertvalue-message" id="consoleassertvalue-message">#</a></span><a aria-hidden="true" class="legacy" id="console_console_assert_value_message"></a></h4> 458<div class="api_metadata"> 459<details class="changelog"><summary>History</summary> 460<table> 461<tbody><tr><th>Version</th><th>Changes</th></tr> 462<tr><td>v10.0.0</td> 463<td><p>The implementation is now spec compliant and does not throw anymore.</p></td></tr> 464<tr><td>v0.1.101</td> 465<td><p><span>Added in: v0.1.101</span></p></td></tr> 466</tbody></table> 467</details> 468</div> 469<ul> 470<li><code>value</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a> The value tested for being truthy.</li> 471<li><code>...message</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a> All arguments besides <code>value</code> are used as error message.</li> 472</ul> 473<p><code>console.assert()</code> writes a message if <code>value</code> is <a href="https://developer.mozilla.org/en-US/docs/Glossary/Falsy">falsy</a> or omitted. It only 474writes a message and does not otherwise affect execution. The output always 475starts with <code>"Assertion failed"</code>. If provided, <code>message</code> is formatted using 476<a href="util.html#utilformatformat-args"><code>util.format()</code></a>.</p> 477<p>If <code>value</code> is <a href="https://developer.mozilla.org/en-US/docs/Glossary/Truthy">truthy</a>, nothing happens.</p> 478<pre><code class="language-js"><span class="hljs-variable language_">console</span>.<span class="hljs-title function_">assert</span>(<span class="hljs-literal">true</span>, <span class="hljs-string">'does nothing'</span>); 479 480<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">assert</span>(<span class="hljs-literal">false</span>, <span class="hljs-string">'Whoops %s work'</span>, <span class="hljs-string">'didn\'t'</span>); 481<span class="hljs-comment">// Assertion failed: Whoops didn't work</span> 482 483<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">assert</span>(); 484<span class="hljs-comment">// Assertion failed</span></code> <button class="copy-button">copy</button></pre> 485<h4><code>console.clear()</code><span><a class="mark" href="#consoleclear" id="consoleclear">#</a></span><a aria-hidden="true" class="legacy" id="console_console_clear"></a></h4> 486<div class="api_metadata"> 487<span>Added in: v8.3.0</span> 488</div> 489<p>When <code>stdout</code> is a TTY, calling <code>console.clear()</code> will attempt to clear the 490TTY. When <code>stdout</code> is not a TTY, this method does nothing.</p> 491<p>The specific operation of <code>console.clear()</code> can vary across operating systems 492and terminal types. For most Linux operating systems, <code>console.clear()</code> 493operates similarly to the <code>clear</code> shell command. On Windows, <code>console.clear()</code> 494will clear only the output in the current terminal viewport for the Node.js 495binary.</p> 496<h4><code>console.count([label])</code><span><a class="mark" href="#consolecountlabel" id="consolecountlabel">#</a></span><a aria-hidden="true" class="legacy" id="console_console_count_label"></a></h4> 497<div class="api_metadata"> 498<span>Added in: v8.3.0</span> 499</div> 500<ul> 501<li><code>label</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> The display label for the counter. <strong>Default:</strong> <code>'default'</code>.</li> 502</ul> 503<p>Maintains an internal counter specific to <code>label</code> and outputs to <code>stdout</code> the 504number of times <code>console.count()</code> has been called with the given <code>label</code>.</p> 505<!-- eslint-skip --> 506<pre><code class="language-js">> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">count</span>() 507<span class="hljs-attr">default</span>: <span class="hljs-number">1</span> 508<span class="hljs-literal">undefined</span> 509> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">count</span>(<span class="hljs-string">'default'</span>) 510<span class="hljs-attr">default</span>: <span class="hljs-number">2</span> 511<span class="hljs-literal">undefined</span> 512> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">count</span>(<span class="hljs-string">'abc'</span>) 513<span class="hljs-attr">abc</span>: <span class="hljs-number">1</span> 514<span class="hljs-literal">undefined</span> 515> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">count</span>(<span class="hljs-string">'xyz'</span>) 516<span class="hljs-attr">xyz</span>: <span class="hljs-number">1</span> 517<span class="hljs-literal">undefined</span> 518> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">count</span>(<span class="hljs-string">'abc'</span>) 519<span class="hljs-attr">abc</span>: <span class="hljs-number">2</span> 520<span class="hljs-literal">undefined</span> 521> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">count</span>() 522<span class="hljs-attr">default</span>: <span class="hljs-number">3</span> 523<span class="hljs-literal">undefined</span> 524></code> <button class="copy-button">copy</button></pre> 525<h4><code>console.countReset([label])</code><span><a class="mark" href="#consolecountresetlabel" id="consolecountresetlabel">#</a></span><a aria-hidden="true" class="legacy" id="console_console_countreset_label"></a></h4> 526<div class="api_metadata"> 527<span>Added in: v8.3.0</span> 528</div> 529<ul> 530<li><code>label</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> The display label for the counter. <strong>Default:</strong> <code>'default'</code>.</li> 531</ul> 532<p>Resets the internal counter specific to <code>label</code>.</p> 533<!-- eslint-skip --> 534<pre><code class="language-js">> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">count</span>(<span class="hljs-string">'abc'</span>); 535<span class="hljs-attr">abc</span>: <span class="hljs-number">1</span> 536<span class="hljs-literal">undefined</span> 537> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">countReset</span>(<span class="hljs-string">'abc'</span>); 538<span class="hljs-literal">undefined</span> 539> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">count</span>(<span class="hljs-string">'abc'</span>); 540<span class="hljs-attr">abc</span>: <span class="hljs-number">1</span> 541<span class="hljs-literal">undefined</span> 542></code> <button class="copy-button">copy</button></pre> 543<h4><code>console.debug(data[, ...args])</code><span><a class="mark" href="#consoledebugdata-args" id="consoledebugdata-args">#</a></span><a aria-hidden="true" class="legacy" id="console_console_debug_data_args"></a></h4> 544<div class="api_metadata"> 545<details class="changelog"><summary>History</summary> 546<table> 547<tbody><tr><th>Version</th><th>Changes</th></tr> 548<tr><td>v8.10.0</td> 549<td><p><code>console.debug</code> is now an alias for <code>console.log</code>.</p></td></tr> 550<tr><td>v8.0.0</td> 551<td><p><span>Added in: v8.0.0</span></p></td></tr> 552</tbody></table> 553</details> 554</div> 555<ul> 556<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 557<li><code>...args</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 558</ul> 559<p>The <code>console.debug()</code> function is an alias for <a href="#consolelogdata-args"><code>console.log()</code></a>.</p> 560<h4><code>console.dir(obj[, options])</code><span><a class="mark" href="#consoledirobj-options" id="consoledirobj-options">#</a></span><a aria-hidden="true" class="legacy" id="console_console_dir_obj_options"></a></h4> 561<div class="api_metadata"> 562<span>Added in: v0.1.101</span> 563</div> 564<ul> 565<li><code>obj</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 566<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 567<ul> 568<li><code>showHidden</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> If <code>true</code> then the object's non-enumerable and symbol 569properties will be shown too. <strong>Default:</strong> <code>false</code>.</li> 570<li><code>depth</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Tells <a href="util.html#utilinspectobject-options"><code>util.inspect()</code></a> how many times to recurse while 571formatting the object. This is useful for inspecting large complicated 572objects. To make it recurse indefinitely, pass <code>null</code>. <strong>Default:</strong> <code>2</code>.</li> 573<li><code>colors</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> If <code>true</code>, then the output will be styled with ANSI color 574codes. Colors are customizable; 575see <a href="util.html#customizing-utilinspect-colors">customizing <code>util.inspect()</code> colors</a>. <strong>Default:</strong> <code>false</code>.</li> 576</ul> 577</li> 578</ul> 579<p>Uses <a href="util.html#utilinspectobject-options"><code>util.inspect()</code></a> on <code>obj</code> and prints the resulting string to <code>stdout</code>. 580This function bypasses any custom <code>inspect()</code> function defined on <code>obj</code>.</p> 581<h4><code>console.dirxml(...data)</code><span><a class="mark" href="#consoledirxmldata" id="consoledirxmldata">#</a></span><a aria-hidden="true" class="legacy" id="console_console_dirxml_data"></a></h4> 582<div class="api_metadata"> 583<details class="changelog"><summary>History</summary> 584<table> 585<tbody><tr><th>Version</th><th>Changes</th></tr> 586<tr><td>v9.3.0</td> 587<td><p><code>console.dirxml</code> now calls <code>console.log</code> for its arguments.</p></td></tr> 588<tr><td>v8.0.0</td> 589<td><p><span>Added in: v8.0.0</span></p></td></tr> 590</tbody></table> 591</details> 592</div> 593<ul> 594<li><code>...data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 595</ul> 596<p>This method calls <code>console.log()</code> passing it the arguments received. 597This method does not produce any XML formatting.</p> 598<h4><code>console.error([data][, ...args])</code><span><a class="mark" href="#consoleerrordata-args" id="consoleerrordata-args">#</a></span><a aria-hidden="true" class="legacy" id="console_console_error_data_args"></a></h4> 599<div class="api_metadata"> 600<span>Added in: v0.1.100</span> 601</div> 602<ul> 603<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 604<li><code>...args</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 605</ul> 606<p>Prints to <code>stderr</code> with newline. Multiple arguments can be passed, with the 607first used as the primary message and all additional used as substitution 608values similar to <a href="http://man7.org/linux/man-pages/man3/printf.3.html"><code>printf(3)</code></a> (the arguments are all passed to 609<a href="util.html#utilformatformat-args"><code>util.format()</code></a>).</p> 610<pre><code class="language-js"><span class="hljs-keyword">const</span> code = <span class="hljs-number">5</span>; 611<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'error #%d'</span>, code); 612<span class="hljs-comment">// Prints: error #5, to stderr</span> 613<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'error'</span>, code); 614<span class="hljs-comment">// Prints: error 5, to stderr</span></code> <button class="copy-button">copy</button></pre> 615<p>If formatting elements (e.g. <code>%d</code>) are not found in the first string then 616<a href="util.html#utilinspectobject-options"><code>util.inspect()</code></a> is called on each argument and the resulting string 617values are concatenated. See <a href="util.html#utilformatformat-args"><code>util.format()</code></a> for more information.</p> 618<h4><code>console.group([...label])</code><span><a class="mark" href="#consolegrouplabel" id="consolegrouplabel">#</a></span><a aria-hidden="true" class="legacy" id="console_console_group_label"></a></h4> 619<div class="api_metadata"> 620<span>Added in: v8.5.0</span> 621</div> 622<ul> 623<li><code>...label</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 624</ul> 625<p>Increases indentation of subsequent lines by spaces for <code>groupIndentation</code> 626length.</p> 627<p>If one or more <code>label</code>s are provided, those are printed first without the 628additional indentation.</p> 629<h4><code>console.groupCollapsed()</code><span><a class="mark" href="#consolegroupcollapsed" id="consolegroupcollapsed">#</a></span><a aria-hidden="true" class="legacy" id="console_console_groupcollapsed"></a></h4> 630<div class="api_metadata"> 631<span>Added in: v8.5.0</span> 632</div> 633<p>An alias for <a href="#consolegrouplabel"><code>console.group()</code></a>.</p> 634<h4><code>console.groupEnd()</code><span><a class="mark" href="#consolegroupend" id="consolegroupend">#</a></span><a aria-hidden="true" class="legacy" id="console_console_groupend"></a></h4> 635<div class="api_metadata"> 636<span>Added in: v8.5.0</span> 637</div> 638<p>Decreases indentation of subsequent lines by spaces for <code>groupIndentation</code> 639length.</p> 640<h4><code>console.info([data][, ...args])</code><span><a class="mark" href="#consoleinfodata-args" id="consoleinfodata-args">#</a></span><a aria-hidden="true" class="legacy" id="console_console_info_data_args"></a></h4> 641<div class="api_metadata"> 642<span>Added in: v0.1.100</span> 643</div> 644<ul> 645<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 646<li><code>...args</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 647</ul> 648<p>The <code>console.info()</code> function is an alias for <a href="#consolelogdata-args"><code>console.log()</code></a>.</p> 649<h4><code>console.log([data][, ...args])</code><span><a class="mark" href="#consolelogdata-args" id="consolelogdata-args">#</a></span><a aria-hidden="true" class="legacy" id="console_console_log_data_args"></a></h4> 650<div class="api_metadata"> 651<span>Added in: v0.1.100</span> 652</div> 653<ul> 654<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 655<li><code>...args</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 656</ul> 657<p>Prints to <code>stdout</code> with newline. Multiple arguments can be passed, with the 658first used as the primary message and all additional used as substitution 659values similar to <a href="http://man7.org/linux/man-pages/man3/printf.3.html"><code>printf(3)</code></a> (the arguments are all passed to 660<a href="util.html#utilformatformat-args"><code>util.format()</code></a>).</p> 661<pre><code class="language-js"><span class="hljs-keyword">const</span> count = <span class="hljs-number">5</span>; 662<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'count: %d'</span>, count); 663<span class="hljs-comment">// Prints: count: 5, to stdout</span> 664<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'count:'</span>, count); 665<span class="hljs-comment">// Prints: count: 5, to stdout</span></code> <button class="copy-button">copy</button></pre> 666<p>See <a href="util.html#utilformatformat-args"><code>util.format()</code></a> for more information.</p> 667<h4><code>console.table(tabularData[, properties])</code><span><a class="mark" href="#consoletabletabulardata-properties" id="consoletabletabulardata-properties">#</a></span><a aria-hidden="true" class="legacy" id="console_console_table_tabulardata_properties"></a></h4> 668<div class="api_metadata"> 669<span>Added in: v10.0.0</span> 670</div> 671<ul> 672<li><code>tabularData</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 673<li><code>properties</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string[]></a> Alternate properties for constructing the table.</li> 674</ul> 675<p>Try to construct a table with the columns of the properties of <code>tabularData</code> 676(or use <code>properties</code>) and rows of <code>tabularData</code> and log it. Falls back to just 677logging the argument if it can't be parsed as tabular.</p> 678<pre><code class="language-js"><span class="hljs-comment">// These can't be parsed as tabular data</span> 679<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">table</span>(<span class="hljs-title class_">Symbol</span>()); 680<span class="hljs-comment">// Symbol()</span> 681 682<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">table</span>(<span class="hljs-literal">undefined</span>); 683<span class="hljs-comment">// undefined</span> 684 685<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">table</span>([{ <span class="hljs-attr">a</span>: <span class="hljs-number">1</span>, <span class="hljs-attr">b</span>: <span class="hljs-string">'Y'</span> }, { <span class="hljs-attr">a</span>: <span class="hljs-string">'Z'</span>, <span class="hljs-attr">b</span>: <span class="hljs-number">2</span> }]); 686<span class="hljs-comment">// ┌─────────┬─────┬─────┐</span> 687<span class="hljs-comment">// │ (index) │ a │ b │</span> 688<span class="hljs-comment">// ├─────────┼─────┼─────┤</span> 689<span class="hljs-comment">// │ 0 │ 1 │ 'Y' │</span> 690<span class="hljs-comment">// │ 1 │ 'Z' │ 2 │</span> 691<span class="hljs-comment">// └─────────┴─────┴─────┘</span> 692 693<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">table</span>([{ <span class="hljs-attr">a</span>: <span class="hljs-number">1</span>, <span class="hljs-attr">b</span>: <span class="hljs-string">'Y'</span> }, { <span class="hljs-attr">a</span>: <span class="hljs-string">'Z'</span>, <span class="hljs-attr">b</span>: <span class="hljs-number">2</span> }], [<span class="hljs-string">'a'</span>]); 694<span class="hljs-comment">// ┌─────────┬─────┐</span> 695<span class="hljs-comment">// │ (index) │ a │</span> 696<span class="hljs-comment">// ├─────────┼─────┤</span> 697<span class="hljs-comment">// │ 0 │ 1 │</span> 698<span class="hljs-comment">// │ 1 │ 'Z' │</span> 699<span class="hljs-comment">// └─────────┴─────┘</span></code> <button class="copy-button">copy</button></pre> 700<h4><code>console.time([label])</code><span><a class="mark" href="#consoletimelabel" id="consoletimelabel">#</a></span><a aria-hidden="true" class="legacy" id="console_console_time_label"></a></h4> 701<div class="api_metadata"> 702<span>Added in: v0.1.104</span> 703</div> 704<ul> 705<li><code>label</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> <strong>Default:</strong> <code>'default'</code></li> 706</ul> 707<p>Starts a timer that can be used to compute the duration of an operation. Timers 708are identified by a unique <code>label</code>. Use the same <code>label</code> when calling 709<a href="#consoletimeendlabel"><code>console.timeEnd()</code></a> to stop the timer and output the elapsed time in 710suitable time units to <code>stdout</code>. For example, if the elapsed 711time is 3869ms, <code>console.timeEnd()</code> displays "3.869s".</p> 712<h4><code>console.timeEnd([label])</code><span><a class="mark" href="#consoletimeendlabel" id="consoletimeendlabel">#</a></span><a aria-hidden="true" class="legacy" id="console_console_timeend_label"></a></h4> 713<div class="api_metadata"> 714<details class="changelog"><summary>History</summary> 715<table> 716<tbody><tr><th>Version</th><th>Changes</th></tr> 717<tr><td>v13.0.0</td> 718<td><p>The elapsed time is displayed with a suitable time unit.</p></td></tr> 719<tr><td>v6.0.0</td> 720<td><p>This method no longer supports multiple calls that don't map to individual <code>console.time()</code> calls; see below for details.</p></td></tr> 721<tr><td>v0.1.104</td> 722<td><p><span>Added in: v0.1.104</span></p></td></tr> 723</tbody></table> 724</details> 725</div> 726<ul> 727<li><code>label</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> <strong>Default:</strong> <code>'default'</code></li> 728</ul> 729<p>Stops a timer that was previously started by calling <a href="#consoletimelabel"><code>console.time()</code></a> and 730prints the result to <code>stdout</code>:</p> 731<pre><code class="language-js"><span class="hljs-variable language_">console</span>.<span class="hljs-title function_">time</span>(<span class="hljs-string">'bunch-of-stuff'</span>); 732<span class="hljs-comment">// Do a bunch of stuff.</span> 733<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">timeEnd</span>(<span class="hljs-string">'bunch-of-stuff'</span>); 734<span class="hljs-comment">// Prints: bunch-of-stuff: 225.438ms</span></code> <button class="copy-button">copy</button></pre> 735<h4><code>console.timeLog([label][, ...data])</code><span><a class="mark" href="#consoletimeloglabel-data" id="consoletimeloglabel-data">#</a></span><a aria-hidden="true" class="legacy" id="console_console_timelog_label_data"></a></h4> 736<div class="api_metadata"> 737<span>Added in: v10.7.0</span> 738</div> 739<ul> 740<li><code>label</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> <strong>Default:</strong> <code>'default'</code></li> 741<li><code>...data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 742</ul> 743<p>For a timer that was previously started by calling <a href="#consoletimelabel"><code>console.time()</code></a>, prints 744the elapsed time and other <code>data</code> arguments to <code>stdout</code>:</p> 745<pre><code class="language-js"><span class="hljs-variable language_">console</span>.<span class="hljs-title function_">time</span>(<span class="hljs-string">'process'</span>); 746<span class="hljs-keyword">const</span> value = <span class="hljs-title function_">expensiveProcess1</span>(); <span class="hljs-comment">// Returns 42</span> 747<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">timeLog</span>(<span class="hljs-string">'process'</span>, value); 748<span class="hljs-comment">// Prints "process: 365.227ms 42".</span> 749<span class="hljs-title function_">doExpensiveProcess2</span>(value); 750<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">timeEnd</span>(<span class="hljs-string">'process'</span>);</code> <button class="copy-button">copy</button></pre> 751<h4><code>console.trace([message][, ...args])</code><span><a class="mark" href="#consoletracemessage-args" id="consoletracemessage-args">#</a></span><a aria-hidden="true" class="legacy" id="console_console_trace_message_args"></a></h4> 752<div class="api_metadata"> 753<span>Added in: v0.1.104</span> 754</div> 755<ul> 756<li><code>message</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 757<li><code>...args</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 758</ul> 759<p>Prints to <code>stderr</code> the string <code>'Trace: '</code>, followed by the <a href="util.html#utilformatformat-args"><code>util.format()</code></a> 760formatted message and stack trace to the current position in the code.</p> 761<pre><code class="language-js"><span class="hljs-variable language_">console</span>.<span class="hljs-title function_">trace</span>(<span class="hljs-string">'Show me'</span>); 762<span class="hljs-comment">// Prints: (stack trace will vary based on where trace is called)</span> 763<span class="hljs-comment">// Trace: Show me</span> 764<span class="hljs-comment">// at repl:2:9</span> 765<span class="hljs-comment">// at REPLServer.defaultEval (repl.js:248:27)</span> 766<span class="hljs-comment">// at bound (domain.js:287:14)</span> 767<span class="hljs-comment">// at REPLServer.runBound [as eval] (domain.js:300:12)</span> 768<span class="hljs-comment">// at REPLServer.<anonymous> (repl.js:412:12)</span> 769<span class="hljs-comment">// at emitOne (events.js:82:20)</span> 770<span class="hljs-comment">// at REPLServer.emit (events.js:169:7)</span> 771<span class="hljs-comment">// at REPLServer.Interface._onLine (readline.js:210:10)</span> 772<span class="hljs-comment">// at REPLServer.Interface._line (readline.js:549:8)</span> 773<span class="hljs-comment">// at REPLServer.Interface._ttyWrite (readline.js:826:14)</span></code> <button class="copy-button">copy</button></pre> 774<h4><code>console.warn([data][, ...args])</code><span><a class="mark" href="#consolewarndata-args" id="consolewarndata-args">#</a></span><a aria-hidden="true" class="legacy" id="console_console_warn_data_args"></a></h4> 775<div class="api_metadata"> 776<span>Added in: v0.1.100</span> 777</div> 778<ul> 779<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 780<li><code>...args</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 781</ul> 782<p>The <code>console.warn()</code> function is an alias for <a href="#consoleerrordata-args"><code>console.error()</code></a>.</p> 783</section><section><h3>Inspector only methods<span><a class="mark" href="#inspector-only-methods" id="inspector-only-methods">#</a></span><a aria-hidden="true" class="legacy" id="console_inspector_only_methods"></a></h3> 784<p>The following methods are exposed by the V8 engine in the general API but do 785not display anything unless used in conjunction with the <a href="debugger.html">inspector</a> 786(<code>--inspect</code> flag).</p> 787<h4><code>console.profile([label])</code><span><a class="mark" href="#consoleprofilelabel" id="consoleprofilelabel">#</a></span><a aria-hidden="true" class="legacy" id="console_console_profile_label"></a></h4> 788<div class="api_metadata"> 789<span>Added in: v8.0.0</span> 790</div> 791<ul> 792<li><code>label</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 793</ul> 794<p>This method does not display anything unless used in the inspector. The 795<code>console.profile()</code> method starts a JavaScript CPU profile with an optional 796label until <a href="#consoleprofileendlabel"><code>console.profileEnd()</code></a> is called. The profile is then added to 797the <strong>Profile</strong> panel of the inspector.</p> 798<pre><code class="language-js"><span class="hljs-variable language_">console</span>.<span class="hljs-title function_">profile</span>(<span class="hljs-string">'MyLabel'</span>); 799<span class="hljs-comment">// Some code</span> 800<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">profileEnd</span>(<span class="hljs-string">'MyLabel'</span>); 801<span class="hljs-comment">// Adds the profile 'MyLabel' to the Profiles panel of the inspector.</span></code> <button class="copy-button">copy</button></pre> 802<h4><code>console.profileEnd([label])</code><span><a class="mark" href="#consoleprofileendlabel" id="consoleprofileendlabel">#</a></span><a aria-hidden="true" class="legacy" id="console_console_profileend_label"></a></h4> 803<div class="api_metadata"> 804<span>Added in: v8.0.0</span> 805</div> 806<ul> 807<li><code>label</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 808</ul> 809<p>This method does not display anything unless used in the inspector. Stops the 810current JavaScript CPU profiling session if one has been started and prints 811the report to the <strong>Profiles</strong> panel of the inspector. See 812<a href="#consoleprofilelabel"><code>console.profile()</code></a> for an example.</p> 813<p>If this method is called without a label, the most recently started profile is 814stopped.</p> 815<h4><code>console.timeStamp([label])</code><span><a class="mark" href="#consoletimestamplabel" id="consoletimestamplabel">#</a></span><a aria-hidden="true" class="legacy" id="console_console_timestamp_label"></a></h4> 816<div class="api_metadata"> 817<span>Added in: v8.0.0</span> 818</div> 819<ul> 820<li><code>label</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 821</ul> 822<p>This method does not display anything unless used in the inspector. The 823<code>console.timeStamp()</code> method adds an event with the label <code>'label'</code> to the 824<strong>Timeline</strong> panel of the inspector.</p></section> 825 <!-- API END --> 826 </div> 827 </div> 828 </div> 829</body> 830</html> 831