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<h1>Node.js v12.22.9 Documentation</h1>
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<h2>Table of Contents</h2>
<ul>
<li><a href="#string_decoder_string_decoder">String decoder</a><ul>
<li><a href="#string_decoder_class_stringdecoder">Class: <code>StringDecoder</code></a><ul>
<li><a href="#string_decoder_new_stringdecoder_encoding"><code>new StringDecoder([encoding])</code></a></li>
<li><a href="#string_decoder_stringdecoder_end_buffer"><code>stringDecoder.end([buffer])</code></a></li>
<li><a href="#string_decoder_stringdecoder_write_buffer"><code>stringDecoder.write(buffer)</code></a></li>
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<h1>String decoder<span><a class="mark" href="#string_decoder_string_decoder" id="string_decoder_string_decoder">#</a></span></h1>
<!--introduced_in=v0.10.0-->
<blockquote>
<p>Stability: 2 - Stable</p>
</blockquote>
<!-- source_link=lib/string_decoder.js -->
<p>The <code>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('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('string_decoder');
const decoder = new StringDecoder('utf8');
const cent = Buffer.from([0xC2, 0xA2]);
console.log(decoder.write(cent));
const euro = Buffer.from([0xE2, 0x82, 0xAC]);
console.log(decoder.write(euro));
</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('string_decoder');
const decoder = new StringDecoder('utf8');
decoder.write(Buffer.from([0xE2]));
decoder.write(Buffer.from([0x82]));
console.log(decoder.end(Buffer.from([0xAC])));
</code></pre>
<h2>Class: <code>StringDecoder</code><span><a class="mark" href="#string_decoder_class_stringdecoder" id="string_decoder_class_stringdecoder">#</a></span></h2>
<h3><code>new StringDecoder([encoding])</code><span><a class="mark" href="#string_decoder_new_stringdecoder_encoding" id="string_decoder_new_stringdecoder_encoding">#</a></span></h3>
<div class="api_metadata">
<span>Added in: v0.1.99</span>
</div><ul>
<li><code>encoding</code> {string} The character <a href="buffer.html#buffer_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>
<h3><code>stringDecoder.end([buffer])</code><span><a class="mark" href="#string_decoder_stringdecoder_end_buffer" id="string_decoder_stringdecoder_end_buffer">#</a></span></h3>
<div class="api_metadata">
<span>Added in: v0.9.3</span>
</div><ul>
<li><code>buffer</code> {Buffer|TypedArray|DataView} A <code>Buffer</code>, or <code>TypedArray</code>, or
<code>DataView</code> containing the bytes to decode.</li>
<li>Returns: {string}</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.</p>
<h3><code>stringDecoder.write(buffer)</code><span><a class="mark" href="#string_decoder_stringdecoder_write_buffer" id="string_decoder_stringdecoder_write_buffer">#</a></span></h3>
<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> {Buffer|TypedArray|DataView} A <code>Buffer</code>, or <code>TypedArray</code>, or
<code>DataView</code> containing the bytes to decode.</li>
<li>Returns: {string}</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>
<!-- API END -->
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