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class="expanded-arrow">▼</span> Other versions </a> <div class="picker"><ol id="alt-docs"><li><a href="https://nodejs.org/docs/latest-v18.x/api/string_decoder.html">18.x <b>LTS</b></a></li> <li><a href="https://nodejs.org/docs/latest-v17.x/api/string_decoder.html">17.x</a></li> <li><a href="https://nodejs.org/docs/latest-v16.x/api/string_decoder.html">16.x <b>LTS</b></a></li> <li><a href="https://nodejs.org/docs/latest-v15.x/api/string_decoder.html">15.x</a></li> <li><a href="https://nodejs.org/docs/latest-v14.x/api/string_decoder.html">14.x</a></li> <li><a href="https://nodejs.org/docs/latest-v13.x/api/string_decoder.html">13.x</a></li> <li><a href="https://nodejs.org/docs/latest-v12.x/api/string_decoder.html">12.x</a></li> <li><a href="https://nodejs.org/docs/latest-v11.x/api/string_decoder.html">11.x</a></li> <li><a href="https://nodejs.org/docs/latest-v10.x/api/string_decoder.html">10.x</a></li> <li><a href="https://nodejs.org/docs/latest-v9.x/api/string_decoder.html">9.x</a></li> <li><a href="https://nodejs.org/docs/latest-v8.x/api/string_decoder.html">8.x</a></li> <li><a href="https://nodejs.org/docs/latest-v7.x/api/string_decoder.html">7.x</a></li> <li><a href="https://nodejs.org/docs/latest-v6.x/api/string_decoder.html">6.x</a></li> <li><a href="https://nodejs.org/docs/latest-v5.x/api/string_decoder.html">5.x</a></li> <li><a href="https://nodejs.org/docs/latest-v4.x/api/string_decoder.html">4.x</a></li> <li><a href="https://nodejs.org/docs/latest-v0.12.x/api/string_decoder.html">0.12.x</a></li> <li><a href="https://nodejs.org/docs/latest-v0.10.x/api/string_decoder.html">0.10.x</a></li></ol></div> </li> <li class="picker-header"> <a href="#"> <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> Options </a> <div class="picker"> <ul> <li> <a href="all.html">View on single page</a> </li> <li> <a href="string_decoder.json">View as JSON</a> </li> <li class="edit_on_github"><a href="https://github.com/nodejs/node/edit/master/doc/api/string_decoder.md">Edit on GitHub</a></li> </ul> </div> </li> </ul> </div> <hr> </header> <details id="toc" open><summary>Table of contents</summary><ul> <li><a href="#string-decoder">String decoder</a><ul> <li><a href="#class-stringdecoder">Class: <code>StringDecoder</code></a><ul> <li><a href="#new-stringdecoderencoding"><code>new StringDecoder([encoding])</code></a></li> <li><a href="#stringdecoderendbuffer"><code>stringDecoder.end([buffer])</code></a></li> <li><a href="#stringdecoderwritebuffer"><code>stringDecoder.write(buffer)</code></a></li> </ul> </li> </ul> </li> </ul> </details> <div id="apicontent"> <h2>String decoder<span><a class="mark" href="#string-decoder" id="string-decoder">#</a></span><a aria-hidden="true" class="legacy" id="string_decoder_string_decoder"></a></h2> <!--introduced_in=v0.10.0--> <blockquote> <p>Stability: 2 - Stable</p> </blockquote> <!-- source_link=lib/string_decoder.js --> <p>The <code>node:string_decoder</code> module provides an API for decoding <code>Buffer</code> objects into strings in a manner that preserves encoded multi-byte UTF-8 and UTF-16 characters. It can be accessed using:</p> <pre><code class="language-js">const { StringDecoder } = require('node:string_decoder'); </code></pre> <p>The following example shows the basic use of the <code>StringDecoder</code> class.</p> <pre><code class="language-js">const { StringDecoder } = require('node:string_decoder'); const decoder = new StringDecoder('utf8'); const cent = Buffer.from([0xC2, 0xA2]); console.log(decoder.write(cent)); // Prints: ¢ const euro = Buffer.from([0xE2, 0x82, 0xAC]); console.log(decoder.write(euro)); // Prints: € </code></pre> <p>When a <code>Buffer</code> instance is written to the <code>StringDecoder</code> instance, an internal buffer is used to ensure that the decoded string does not contain any incomplete multibyte characters. These are held in the buffer until the next call to <code>stringDecoder.write()</code> or until <code>stringDecoder.end()</code> is called.</p> <p>In the following example, the three UTF-8 encoded bytes of the European Euro symbol (<code>€</code>) are written over three separate operations:</p> <pre><code class="language-js">const { StringDecoder } = require('node:string_decoder'); const decoder = new StringDecoder('utf8'); decoder.write(Buffer.from([0xE2])); decoder.write(Buffer.from([0x82])); console.log(decoder.end(Buffer.from([0xAC]))); // Prints: € </code></pre> <section><h3>Class: <code>StringDecoder</code><span><a class="mark" href="#class-stringdecoder" id="class-stringdecoder">#</a></span><a aria-hidden="true" class="legacy" id="string_decoder_class_stringdecoder"></a></h3> <h4><code>new StringDecoder([encoding])</code><span><a class="mark" href="#new-stringdecoderencoding" id="new-stringdecoderencoding">#</a></span><a aria-hidden="true" class="legacy" id="string_decoder_new_stringdecoder_encoding"></a></h4> <div class="api_metadata"> <span>Added in: v0.1.99</span> </div><ul> <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#buffers-and-character-encodings">encoding</a> the <code>StringDecoder</code> will use. <strong>Default:</strong> <code>'utf8'</code>.</li> </ul> <p>Creates a new <code>StringDecoder</code> instance.</p> <h4><code>stringDecoder.end([buffer])</code><span><a class="mark" href="#stringdecoderendbuffer" id="stringdecoderendbuffer">#</a></span><a aria-hidden="true" class="legacy" id="string_decoder_stringdecoder_end_buffer"></a></h4> <div class="api_metadata"> <span>Added in: v0.9.3</span> </div><ul> <li><code>buffer</code> {string|Buffer|TypedArray|DataView} The bytes to decode.</li> <li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> </ul> <p>Returns any remaining input stored in the internal buffer as a string. Bytes representing incomplete UTF-8 and UTF-16 characters will be replaced with substitution characters appropriate for the character encoding.</p> <p>If the <code>buffer</code> argument is provided, one final call to <code>stringDecoder.write()</code> is performed before returning the remaining input. After <code>end()</code> is called, the <code>stringDecoder</code> object can be reused for new input.</p> <h4><code>stringDecoder.write(buffer)</code><span><a class="mark" href="#stringdecoderwritebuffer" id="stringdecoderwritebuffer">#</a></span><a aria-hidden="true" class="legacy" id="string_decoder_stringdecoder_write_buffer"></a></h4> <div class="api_metadata"> <details class="changelog"><summary>History</summary> <table> <tr><th>Version</th><th>Changes</th></tr> <tr><td>v8.0.0</td> <td><p>Each invalid character is now replaced by a single replacement character instead of one for each individual byte.</p> </td></tr> <tr><td>v0.1.99</td> <td><p><span>Added in: v0.1.99</span></p> </td></tr> </table> </details> </div><ul> <li><code>buffer</code> {string|Buffer|TypedArray|DataView} The bytes to decode.</li> <li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> </ul> <p>Returns a decoded string, ensuring that any incomplete multibyte characters at the end of the <code>Buffer</code>, or <code>TypedArray</code>, or <code>DataView</code> are omitted from the returned string and stored in an internal buffer for the next call to <code>stringDecoder.write()</code> or <code>stringDecoder.end()</code>.</p> </section> <!-- API END --> </div> </div> </div> </body> </html>