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="v14.19.1"> 7 <title>Punycode | Node.js v14.19.1 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/punycode.html"> 12</head> 13<body class="alt apidoc" id="api-section-punycode"> 14 <div id="content" class="clearfix"> 15 <div id="column2" class="interior"> 16 <div id="intro" class="interior"> 17 <a href="/" title="Go back to the home page"> 18 Node.js 19 </a> 20 </div> 21 <ul> 22<li><a href="documentation.html" class="nav-documentation">About this documentation</a></li> 23<li><a href="synopsis.html" class="nav-synopsis">Usage and example</a></li> 24</ul> 25<hr class="line"> 26<ul> 27<li><a href="assert.html" class="nav-assert">Assertion testing</a></li> 28<li><a href="async_hooks.html" class="nav-async_hooks">Async hooks</a></li> 29<li><a href="buffer.html" class="nav-buffer">Buffer</a></li> 30<li><a href="addons.html" class="nav-addons">C++ addons</a></li> 31<li><a href="n-api.html" class="nav-n-api">C/C++ addons with Node-API</a></li> 32<li><a href="embedding.html" class="nav-embedding">C++ embedder API</a></li> 33<li><a href="child_process.html" class="nav-child_process">Child processes</a></li> 34<li><a href="cluster.html" class="nav-cluster">Cluster</a></li> 35<li><a href="cli.html" class="nav-cli">Command-line options</a></li> 36<li><a href="console.html" class="nav-console">Console</a></li> 37<li><a href="corepack.html" class="nav-corepack">Corepack</a></li> 38<li><a href="crypto.html" class="nav-crypto">Crypto</a></li> 39<li><a href="debugger.html" class="nav-debugger">Debugger</a></li> 40<li><a href="deprecations.html" class="nav-deprecations">Deprecated APIs</a></li> 41<li><a href="diagnostics_channel.html" class="nav-diagnostics_channel">Diagnostics Channel</a></li> 42<li><a href="dns.html" class="nav-dns">DNS</a></li> 43<li><a href="domain.html" class="nav-domain">Domain</a></li> 44<li><a href="errors.html" class="nav-errors">Errors</a></li> 45<li><a href="events.html" class="nav-events">Events</a></li> 46<li><a href="fs.html" class="nav-fs">File system</a></li> 47<li><a href="globals.html" class="nav-globals">Globals</a></li> 48<li><a href="http.html" class="nav-http">HTTP</a></li> 49<li><a href="http2.html" class="nav-http2">HTTP/2</a></li> 50<li><a href="https.html" class="nav-https">HTTPS</a></li> 51<li><a href="inspector.html" class="nav-inspector">Inspector</a></li> 52<li><a href="intl.html" class="nav-intl">Internationalization</a></li> 53<li><a href="modules.html" class="nav-modules">Modules: CommonJS modules</a></li> 54<li><a href="esm.html" class="nav-esm">Modules: ECMAScript modules</a></li> 55<li><a href="module.html" class="nav-module">Modules: <code>module</code> API</a></li> 56<li><a href="packages.html" class="nav-packages">Modules: Packages</a></li> 57<li><a href="net.html" class="nav-net">Net</a></li> 58<li><a href="os.html" class="nav-os">OS</a></li> 59<li><a href="path.html" class="nav-path">Path</a></li> 60<li><a href="perf_hooks.html" class="nav-perf_hooks">Performance hooks</a></li> 61<li><a href="policy.html" class="nav-policy">Policies</a></li> 62<li><a href="process.html" class="nav-process">Process</a></li> 63<li><a href="punycode.html" class="nav-punycode active">Punycode</a></li> 64<li><a href="querystring.html" class="nav-querystring">Query strings</a></li> 65<li><a href="readline.html" class="nav-readline">Readline</a></li> 66<li><a href="repl.html" class="nav-repl">REPL</a></li> 67<li><a href="report.html" class="nav-report">Report</a></li> 68<li><a href="stream.html" class="nav-stream">Stream</a></li> 69<li><a href="string_decoder.html" class="nav-string_decoder">String decoder</a></li> 70<li><a href="timers.html" class="nav-timers">Timers</a></li> 71<li><a href="tls.html" class="nav-tls">TLS/SSL</a></li> 72<li><a href="tracing.html" class="nav-tracing">Trace events</a></li> 73<li><a href="tty.html" class="nav-tty">TTY</a></li> 74<li><a href="dgram.html" class="nav-dgram">UDP/datagram</a></li> 75<li><a href="url.html" class="nav-url">URL</a></li> 76<li><a href="util.html" class="nav-util">Utilities</a></li> 77<li><a href="v8.html" class="nav-v8">V8</a></li> 78<li><a href="vm.html" class="nav-vm">VM</a></li> 79<li><a href="wasi.html" class="nav-wasi">WASI</a></li> 80<li><a href="worker_threads.html" class="nav-worker_threads">Worker threads</a></li> 81<li><a href="zlib.html" class="nav-zlib">Zlib</a></li> 82</ul> 83<hr class="line"> 84<ul> 85<li><a href="https://github.com/nodejs/node" class="nav-https-github-com-nodejs-node">Code repository and issue tracker</a></li> 86</ul> 87 </div> 88 89 <div id="column1" data-id="punycode" class="interior"> 90 <header> 91 <div class="header-container"> 92 <h1>Node.js v14.19.1 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 3.91l-1.41-1.41-1.79 1.79 1.41 1.41 1.79-1.79zm-3.21 13.7l1.79 1.8 1.41-1.41-1.8-1.79-1.4 1.4zM20 10.5v2h3v-2h-3zm-8-5c-3.31 0-6 2.69-6 6s2.69 6 6 6 6-2.69 6-6-2.69-6-6-6zm-1 16.95h2V19.5h-2v2.95zm-7.45-3.91l1.41 1.41 1.79-1.8-1.41-1.41-1.79 1.8z"/> 102 </svg> 103 </button> 104 </div> 105 <div id="gtoc"> 106 <ul> 107 <li> 108 <a href="index.html">Index</a> 109 </li> 110 <li> 111 <a href="all.html">View on single page</a> 112 </li> 113 <li> 114 <a href="punycode.json">View as JSON</a> 115 </li> 116 117 <li class="version-picker"> 118 <a href="#">View another version <span>▼</span></a> 119 <ol class="version-picker"><li><a href="https://nodejs.org/docs/latest-v17.x/api/punycode.html">17.x</a></li> 120<li><a href="https://nodejs.org/docs/latest-v16.x/api/punycode.html">16.x <b>LTS</b></a></li> 121<li><a href="https://nodejs.org/docs/latest-v15.x/api/punycode.html">15.x</a></li> 122<li><a href="https://nodejs.org/docs/latest-v14.x/api/punycode.html">14.x <b>LTS</b></a></li> 123<li><a href="https://nodejs.org/docs/latest-v13.x/api/punycode.html">13.x</a></li> 124<li><a href="https://nodejs.org/docs/latest-v12.x/api/punycode.html">12.x <b>LTS</b></a></li> 125<li><a href="https://nodejs.org/docs/latest-v11.x/api/punycode.html">11.x</a></li> 126<li><a href="https://nodejs.org/docs/latest-v10.x/api/punycode.html">10.x</a></li> 127<li><a href="https://nodejs.org/docs/latest-v9.x/api/punycode.html">9.x</a></li> 128<li><a href="https://nodejs.org/docs/latest-v8.x/api/punycode.html">8.x</a></li> 129<li><a href="https://nodejs.org/docs/latest-v7.x/api/punycode.html">7.x</a></li> 130<li><a href="https://nodejs.org/docs/latest-v6.x/api/punycode.html">6.x</a></li> 131<li><a href="https://nodejs.org/docs/latest-v5.x/api/punycode.html">5.x</a></li> 132<li><a href="https://nodejs.org/docs/latest-v4.x/api/punycode.html">4.x</a></li> 133<li><a href="https://nodejs.org/docs/latest-v0.12.x/api/punycode.html">0.12.x</a></li> 134<li><a href="https://nodejs.org/docs/latest-v0.10.x/api/punycode.html">0.10.x</a></li></ol> 135 </li> 136 137 <li class="edit_on_github"><a href="https://github.com/nodejs/node/edit/master/doc/api/punycode.md">Edit on GitHub</a></li> 138 </ul> 139 </div> 140 <hr> 141 </header> 142 143 <details id="toc" open><summary>Table of contents</summary><ul> 144<li><span class="stability_0"><a href="#punycode_punycode">Punycode</a></span> 145<ul> 146<li><a href="#punycode_punycode_decode_string"><code>punycode.decode(string)</code></a></li> 147<li><a href="#punycode_punycode_encode_string"><code>punycode.encode(string)</code></a></li> 148<li><a href="#punycode_punycode_toascii_domain"><code>punycode.toASCII(domain)</code></a></li> 149<li><a href="#punycode_punycode_tounicode_domain"><code>punycode.toUnicode(domain)</code></a></li> 150<li><a href="#punycode_punycode_ucs2"><code>punycode.ucs2</code></a> 151<ul> 152<li><a href="#punycode_punycode_ucs2_decode_string"><code>punycode.ucs2.decode(string)</code></a></li> 153<li><a href="#punycode_punycode_ucs2_encode_codepoints"><code>punycode.ucs2.encode(codePoints)</code></a></li> 154</ul> 155</li> 156<li><a href="#punycode_punycode_version"><code>punycode.version</code></a></li> 157</ul> 158</li> 159</ul></details> 160 161 <div id="apicontent"> 162 <h2>Punycode<span><a class="mark" href="#punycode_punycode" id="punycode_punycode">#</a></span></h2> 163<div class="api_metadata"> 164<span>Deprecated since: v7.0.0</span> 165</div> 166 167<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated</div><p></p> 168<p><strong>Source Code:</strong> <a href="https://github.com/nodejs/node/blob/v14.19.1/lib/punycode.js">lib/punycode.js</a></p> 169<p><strong>The version of the punycode module bundled in Node.js is being deprecated</strong>. 170In a future major version of Node.js this module will be removed. Users 171currently depending on the <code>punycode</code> module should switch to using the 172userland-provided <a href="https://github.com/bestiejs/punycode.js">Punycode.js</a> module instead. For punycode-based URL 173encoding, see <a href="url.html#url_url_domaintoascii_domain"><code>url.domainToASCII</code></a> or, more generally, the 174<a href="url.html#url_the_whatwg_url_api">WHATWG URL API</a>.</p> 175<p>The <code>punycode</code> module is a bundled version of the <a href="https://github.com/bestiejs/punycode.js">Punycode.js</a> module. It 176can be accessed using:</p> 177<pre><code class="language-js"><span class="hljs-keyword">const</span> punycode = <span class="hljs-built_in">require</span>(<span class="hljs-string">'punycode'</span>);</code></pre> 178<p><a href="https://tools.ietf.org/html/rfc3492">Punycode</a> is a character encoding scheme defined by RFC 3492 that is 179primarily intended for use in Internationalized Domain Names. Because host 180names in URLs are limited to ASCII characters only, Domain Names that contain 181non-ASCII characters must be converted into ASCII using the Punycode scheme. 182For instance, the Japanese character that translates into the English word, 183<code>'example'</code> is <code>'例'</code>. The Internationalized Domain Name, <code>'例.com'</code> (equivalent 184to <code>'example.com'</code>) is represented by Punycode as the ASCII string 185<code>'xn--fsq.com'</code>.</p> 186<p>The <code>punycode</code> module provides a simple implementation of the Punycode standard.</p> 187<p>The <code>punycode</code> module is a third-party dependency used by Node.js and 188made available to developers as a convenience. Fixes or other modifications to 189the module must be directed to the <a href="https://github.com/bestiejs/punycode.js">Punycode.js</a> project.</p> 190<section><h3><code>punycode.decode(string)</code><span><a class="mark" href="#punycode_punycode_decode_string" id="punycode_punycode_decode_string">#</a></span></h3> 191<div class="api_metadata"> 192<span>Added in: v0.5.1</span> 193</div> 194<ul> 195<li><code>string</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 196</ul> 197<p>The <code>punycode.decode()</code> method converts a <a href="https://tools.ietf.org/html/rfc3492">Punycode</a> string of ASCII-only 198characters to the equivalent string of Unicode codepoints.</p> 199<pre><code class="language-js">punycode.<span class="hljs-title function_">decode</span>(<span class="hljs-string">'maana-pta'</span>); <span class="hljs-comment">// 'mañana'</span> 200punycode.<span class="hljs-title function_">decode</span>(<span class="hljs-string">'--dqo34k'</span>); <span class="hljs-comment">// '☃-⌘'</span></code></pre> 201</section><section><h3><code>punycode.encode(string)</code><span><a class="mark" href="#punycode_punycode_encode_string" id="punycode_punycode_encode_string">#</a></span></h3> 202<div class="api_metadata"> 203<span>Added in: v0.5.1</span> 204</div> 205<ul> 206<li><code>string</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 207</ul> 208<p>The <code>punycode.encode()</code> method converts a string of Unicode codepoints to a 209<a href="https://tools.ietf.org/html/rfc3492">Punycode</a> string of ASCII-only characters.</p> 210<pre><code class="language-js">punycode.<span class="hljs-title function_">encode</span>(<span class="hljs-string">'mañana'</span>); <span class="hljs-comment">// 'maana-pta'</span> 211punycode.<span class="hljs-title function_">encode</span>(<span class="hljs-string">'☃-⌘'</span>); <span class="hljs-comment">// '--dqo34k'</span></code></pre> 212</section><section><h3><code>punycode.toASCII(domain)</code><span><a class="mark" href="#punycode_punycode_toascii_domain" id="punycode_punycode_toascii_domain">#</a></span></h3> 213<div class="api_metadata"> 214<span>Added in: v0.6.1</span> 215</div> 216<ul> 217<li><code>domain</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 218</ul> 219<p>The <code>punycode.toASCII()</code> method converts a Unicode string representing an 220Internationalized Domain Name to <a href="https://tools.ietf.org/html/rfc3492">Punycode</a>. Only the non-ASCII parts of the 221domain name will be converted. Calling <code>punycode.toASCII()</code> on a string that 222already only contains ASCII characters will have no effect.</p> 223<pre><code class="language-js"><span class="hljs-comment">// encode domain names</span> 224punycode.<span class="hljs-title function_">toASCII</span>(<span class="hljs-string">'mañana.com'</span>); <span class="hljs-comment">// 'xn--maana-pta.com'</span> 225punycode.<span class="hljs-title function_">toASCII</span>(<span class="hljs-string">'☃-⌘.com'</span>); <span class="hljs-comment">// 'xn----dqo34k.com'</span> 226punycode.<span class="hljs-title function_">toASCII</span>(<span class="hljs-string">'example.com'</span>); <span class="hljs-comment">// 'example.com'</span></code></pre> 227</section><section><h3><code>punycode.toUnicode(domain)</code><span><a class="mark" href="#punycode_punycode_tounicode_domain" id="punycode_punycode_tounicode_domain">#</a></span></h3> 228<div class="api_metadata"> 229<span>Added in: v0.6.1</span> 230</div> 231<ul> 232<li><code>domain</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 233</ul> 234<p>The <code>punycode.toUnicode()</code> method converts a string representing a domain name 235containing <a href="https://tools.ietf.org/html/rfc3492">Punycode</a> encoded characters into Unicode. Only the <a href="https://tools.ietf.org/html/rfc3492">Punycode</a> 236encoded parts of the domain name are be converted.</p> 237<pre><code class="language-js"><span class="hljs-comment">// decode domain names</span> 238punycode.<span class="hljs-title function_">toUnicode</span>(<span class="hljs-string">'xn--maana-pta.com'</span>); <span class="hljs-comment">// 'mañana.com'</span> 239punycode.<span class="hljs-title function_">toUnicode</span>(<span class="hljs-string">'xn----dqo34k.com'</span>); <span class="hljs-comment">// '☃-⌘.com'</span> 240punycode.<span class="hljs-title function_">toUnicode</span>(<span class="hljs-string">'example.com'</span>); <span class="hljs-comment">// 'example.com'</span></code></pre> 241</section><section><h3><code>punycode.ucs2</code><span><a class="mark" href="#punycode_punycode_ucs2" id="punycode_punycode_ucs2">#</a></span></h3> 242<div class="api_metadata"> 243<span>Added in: v0.7.0</span> 244</div> 245<h4><code>punycode.ucs2.decode(string)</code><span><a class="mark" href="#punycode_punycode_ucs2_decode_string" id="punycode_punycode_ucs2_decode_string">#</a></span></h4> 246<div class="api_metadata"> 247<span>Added in: v0.7.0</span> 248</div> 249<ul> 250<li><code>string</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 251</ul> 252<p>The <code>punycode.ucs2.decode()</code> method returns an array containing the numeric 253codepoint values of each Unicode symbol in the string.</p> 254<pre><code class="language-js">punycode.<span class="hljs-property">ucs2</span>.<span class="hljs-title function_">decode</span>(<span class="hljs-string">'abc'</span>); <span class="hljs-comment">// [0x61, 0x62, 0x63]</span> 255<span class="hljs-comment">// surrogate pair for U+1D306 tetragram for centre:</span> 256punycode.<span class="hljs-property">ucs2</span>.<span class="hljs-title function_">decode</span>(<span class="hljs-string">'\uD834\uDF06'</span>); <span class="hljs-comment">// [0x1D306]</span></code></pre> 257<h4><code>punycode.ucs2.encode(codePoints)</code><span><a class="mark" href="#punycode_punycode_ucs2_encode_codepoints" id="punycode_punycode_ucs2_encode_codepoints">#</a></span></h4> 258<div class="api_metadata"> 259<span>Added in: v0.7.0</span> 260</div> 261<ul> 262<li><code>codePoints</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer[]></a></li> 263</ul> 264<p>The <code>punycode.ucs2.encode()</code> method returns a string based on an array of 265numeric code point values.</p> 266<pre><code class="language-js">punycode.<span class="hljs-property">ucs2</span>.<span class="hljs-title function_">encode</span>([<span class="hljs-number">0x61</span>, <span class="hljs-number">0x62</span>, <span class="hljs-number">0x63</span>]); <span class="hljs-comment">// 'abc'</span> 267punycode.<span class="hljs-property">ucs2</span>.<span class="hljs-title function_">encode</span>([<span class="hljs-number">0x1D306</span>]); <span class="hljs-comment">// '\uD834\uDF06'</span></code></pre> 268</section><section><h3><code>punycode.version</code><span><a class="mark" href="#punycode_punycode_version" id="punycode_punycode_version">#</a></span></h3> 269<div class="api_metadata"> 270<span>Added in: v0.6.1</span> 271</div> 272<ul> 273<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 274</ul> 275<p>Returns a string identifying the current <a href="https://github.com/bestiejs/punycode.js">Punycode.js</a> version number.</p></section> 276 <!-- API END --> 277 </div> 278 </div> 279 </div> 280 <script> 281 'use strict'; 282 { 283 const kCustomPreference = 'customDarkTheme'; 284 const userSettings = sessionStorage.getItem(kCustomPreference); 285 const themeToggleButton = document.getElementById('theme-toggle-btn'); 286 if (userSettings === null && window.matchMedia) { 287 const mq = window.matchMedia('(prefers-color-scheme: dark)'); 288 if ('onchange' in mq) { 289 function mqChangeListener(e) { 290 document.body.classList.toggle('dark-mode', e.matches); 291 } 292 mq.addEventListener('change', mqChangeListener); 293 if (themeToggleButton) { 294 themeToggleButton.addEventListener('click', function() { 295 mq.removeEventListener('change', mqChangeListener); 296 }, { once: true }); 297 } 298 } 299 if (mq.matches) { 300 document.body.classList.add('dark-mode'); 301 } 302 } else if (userSettings === 'true') { 303 document.body.classList.add('dark-mode'); 304 } 305 if (themeToggleButton) { 306 themeToggleButton.hidden = false; 307 themeToggleButton.addEventListener('click', function() { 308 sessionStorage.setItem( 309 kCustomPreference, 310 document.body.classList.toggle('dark-mode') 311 ); 312 }); 313 } 314 } 315 </script> 316</body> 317</html> 318