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href="https://nodejs.org/docs/latest-v4.x/api/string_decoder.html">4.x</a></li> 133<li><a href="https://nodejs.org/docs/latest-v0.12.x/api/string_decoder.html">0.12.x</a></li> 134<li><a href="https://nodejs.org/docs/latest-v0.10.x/api/string_decoder.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/string_decoder.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_2"><a href="#string_decoder_string_decoder">String decoder</a></span> 145<ul> 146<li><a href="#string_decoder_class_stringdecoder">Class: <code>StringDecoder</code></a> 147<ul> 148<li><a href="#string_decoder_new_stringdecoder_encoding"><code>new StringDecoder([encoding])</code></a></li> 149<li><a href="#string_decoder_stringdecoder_end_buffer"><code>stringDecoder.end([buffer])</code></a></li> 150<li><a href="#string_decoder_stringdecoder_write_buffer"><code>stringDecoder.write(buffer)</code></a></li> 151</ul> 152</li> 153</ul> 154</li> 155</ul></details> 156 157 <div id="apicontent"> 158 <h2>String decoder<span><a class="mark" href="#string_decoder_string_decoder" id="string_decoder_string_decoder">#</a></span></h2> 159 160<p></p><div class="api_stability api_stability_2"><a href="documentation.html#documentation_stability_index">Stability: 2</a> - Stable</div><p></p> 161<p><strong>Source Code:</strong> <a href="https://github.com/nodejs/node/blob/v14.19.1/lib/string_decoder.js">lib/string_decoder.js</a></p> 162<p>The <code>string_decoder</code> module provides an API for decoding <code>Buffer</code> objects into 163strings in a manner that preserves encoded multi-byte UTF-8 and UTF-16 164characters. It can be accessed using:</p> 165<pre><code class="language-js"><span class="hljs-keyword">const</span> { <span class="hljs-title class_">StringDecoder</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'string_decoder'</span>);</code></pre> 166<p>The following example shows the basic use of the <code>StringDecoder</code> class.</p> 167<pre><code class="language-js"><span class="hljs-keyword">const</span> { <span class="hljs-title class_">StringDecoder</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'string_decoder'</span>); 168<span class="hljs-keyword">const</span> decoder = <span class="hljs-keyword">new</span> <span class="hljs-title class_">StringDecoder</span>(<span class="hljs-string">'utf8'</span>); 169 170<span class="hljs-keyword">const</span> cent = <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>([<span class="hljs-number">0xC2</span>, <span class="hljs-number">0xA2</span>]); 171<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(decoder.<span class="hljs-title function_">write</span>(cent)); 172 173<span class="hljs-keyword">const</span> euro = <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>([<span class="hljs-number">0xE2</span>, <span class="hljs-number">0x82</span>, <span class="hljs-number">0xAC</span>]); 174<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(decoder.<span class="hljs-title function_">write</span>(euro));</code></pre> 175<p>When a <code>Buffer</code> instance is written to the <code>StringDecoder</code> instance, an 176internal buffer is used to ensure that the decoded string does not contain 177any incomplete multibyte characters. These are held in the buffer until the 178next call to <code>stringDecoder.write()</code> or until <code>stringDecoder.end()</code> is called.</p> 179<p>In the following example, the three UTF-8 encoded bytes of the European Euro 180symbol (<code>€</code>) are written over three separate operations:</p> 181<pre><code class="language-js"><span class="hljs-keyword">const</span> { <span class="hljs-title class_">StringDecoder</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'string_decoder'</span>); 182<span class="hljs-keyword">const</span> decoder = <span class="hljs-keyword">new</span> <span class="hljs-title class_">StringDecoder</span>(<span class="hljs-string">'utf8'</span>); 183 184decoder.<span class="hljs-title function_">write</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>([<span class="hljs-number">0xE2</span>])); 185decoder.<span class="hljs-title function_">write</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>([<span class="hljs-number">0x82</span>])); 186<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(decoder.<span class="hljs-title function_">end</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>([<span class="hljs-number">0xAC</span>])));</code></pre> 187<section><h3>Class: <code>StringDecoder</code><span><a class="mark" href="#string_decoder_class_stringdecoder" id="string_decoder_class_stringdecoder">#</a></span></h3> 188<h4><code>new StringDecoder([encoding])</code><span><a class="mark" href="#string_decoder_new_stringdecoder_encoding" id="string_decoder_new_stringdecoder_encoding">#</a></span></h4> 189<div class="api_metadata"> 190<span>Added in: v0.1.99</span> 191</div> 192<ul> 193<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> The character <a href="buffer.html#buffer_buffers_and_character_encodings">encoding</a> the <code>StringDecoder</code> will use. 194<strong>Default:</strong> <code>'utf8'</code>.</li> 195</ul> 196<p>Creates a new <code>StringDecoder</code> instance.</p> 197<h4><code>stringDecoder.end([buffer])</code><span><a class="mark" href="#string_decoder_stringdecoder_end_buffer" id="string_decoder_stringdecoder_end_buffer">#</a></span></h4> 198<div class="api_metadata"> 199<span>Added in: v0.9.3</span> 200</div> 201<ul> 202<li><code>buffer</code> <a href="buffer.html#buffer_class_buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> A <code>Buffer</code>, or <code>TypedArray</code>, or 203<code>DataView</code> containing the bytes to decode.</li> 204<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 205</ul> 206<p>Returns any remaining input stored in the internal buffer as a string. Bytes 207representing incomplete UTF-8 and UTF-16 characters will be replaced with 208substitution characters appropriate for the character encoding.</p> 209<p>If the <code>buffer</code> argument is provided, one final call to <code>stringDecoder.write()</code> 210is performed before returning the remaining input. 211After <code>end()</code> is called, the <code>stringDecoder</code> object can be reused for new input.</p> 212<h4><code>stringDecoder.write(buffer)</code><span><a class="mark" href="#string_decoder_stringdecoder_write_buffer" id="string_decoder_stringdecoder_write_buffer">#</a></span></h4> 213<div class="api_metadata"> 214<details class="changelog"><summary>History</summary> 215<table> 216<tbody><tr><th>Version</th><th>Changes</th></tr> 217<tr><td>v8.0.0</td> 218<td><p>Each invalid character is now replaced by a single replacement character instead of one for each individual byte.</p></td></tr> 219<tr><td>v0.1.99</td> 220<td><p><span>Added in: v0.1.99</span></p></td></tr> 221</tbody></table> 222</details> 223</div> 224<ul> 225<li><code>buffer</code> <a href="buffer.html#buffer_class_buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> A <code>Buffer</code>, or <code>TypedArray</code>, or 226<code>DataView</code> containing the bytes to decode.</li> 227<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 228</ul> 229<p>Returns a decoded string, ensuring that any incomplete multibyte characters at 230the end of the <code>Buffer</code>, or <code>TypedArray</code>, or <code>DataView</code> are omitted from the 231returned string and stored in an internal buffer for the next call to 232<code>stringDecoder.write()</code> or <code>stringDecoder.end()</code>.</p></section> 233 <!-- API END --> 234 </div> 235 </div> 236 </div> 237 <script> 238 'use strict'; 239 { 240 const kCustomPreference = 'customDarkTheme'; 241 const userSettings = sessionStorage.getItem(kCustomPreference); 242 const themeToggleButton = document.getElementById('theme-toggle-btn'); 243 if (userSettings === null && window.matchMedia) { 244 const mq = window.matchMedia('(prefers-color-scheme: dark)'); 245 if ('onchange' in mq) { 246 function mqChangeListener(e) { 247 document.body.classList.toggle('dark-mode', e.matches); 248 } 249 mq.addEventListener('change', mqChangeListener); 250 if (themeToggleButton) { 251 themeToggleButton.addEventListener('click', function() { 252 mq.removeEventListener('change', mqChangeListener); 253 }, { once: true }); 254 } 255 } 256 if (mq.matches) { 257 document.body.classList.add('dark-mode'); 258 } 259 } else if (userSettings === 'true') { 260 document.body.classList.add('dark-mode'); 261 } 262 if (themeToggleButton) { 263 themeToggleButton.hidden = false; 264 themeToggleButton.addEventListener('click', function() { 265 sessionStorage.setItem( 266 kCustomPreference, 267 document.body.classList.toggle('dark-mode') 268 ); 269 }); 270 } 271 } 272 </script> 273</body> 274</html> 275