xref: /third_party/node/doc/api/string_decoder.json (revision 1cb0ef41)

{
  "type": "module",
  "source": "doc/api/string_decoder.md",
  "modules": [
    {
      "textRaw": "String decoder",
      "name": "string_decoder",
      "introduced_in": "v0.10.0",
      "stability": 2,
      "stabilityText": "Stable",
      "desc": "<p><strong>Source Code:</strong> <a href=\"https://github.com/nodejs/node/blob/v18.20.1/lib/string_decoder.js\">lib/string_decoder.js</a></p>\n<p>The <code>node:string_decoder</code> module provides an API for decoding <code>Buffer</code> objects\ninto strings in a manner that preserves encoded multi-byte UTF-8 and UTF-16\ncharacters. It can be accessed using:</p>\n<pre><code class=\"language-js\">const { StringDecoder } = require('node:string_decoder');\n</code></pre>\n<p>The following example shows the basic use of the <code>StringDecoder</code> class.</p>\n<pre><code class=\"language-js\">const { StringDecoder } = require('node:string_decoder');\nconst decoder = new StringDecoder('utf8');\n\nconst cent = Buffer.from([0xC2, 0xA2]);\nconsole.log(decoder.write(cent)); // Prints: ¢\n\nconst euro = Buffer.from([0xE2, 0x82, 0xAC]);\nconsole.log(decoder.write(euro)); // Prints: €\n</code></pre>\n<p>When a <code>Buffer</code> instance is written to the <code>StringDecoder</code> instance, an\ninternal buffer is used to ensure that the decoded string does not contain\nany incomplete multibyte characters. These are held in the buffer until the\nnext call to <code>stringDecoder.write()</code> or until <code>stringDecoder.end()</code> is called.</p>\n<p>In the following example, the three UTF-8 encoded bytes of the European Euro\nsymbol (<code>€</code>) are written over three separate operations:</p>\n<pre><code class=\"language-js\">const { StringDecoder } = require('node:string_decoder');\nconst decoder = new StringDecoder('utf8');\n\ndecoder.write(Buffer.from([0xE2]));\ndecoder.write(Buffer.from([0x82]));\nconsole.log(decoder.end(Buffer.from([0xAC]))); // Prints: €\n</code></pre>",
      "classes": [
        {
          "textRaw": "Class: `StringDecoder`",
          "type": "class",
          "name": "StringDecoder",
          "methods": [
            {
              "textRaw": "`stringDecoder.end([buffer])`",
              "type": "method",
              "name": "end",
              "meta": {
                "added": [
                  "v0.9.3"
                ],
                "changes": []
              },
              "signatures": [
                {
                  "return": {
                    "textRaw": "Returns: {string}",
                    "name": "return",
                    "type": "string"
                  },
                  "params": [
                    {
                      "textRaw": "`buffer` {string|Buffer|TypedArray|DataView} The bytes to decode.",
                      "name": "buffer",
                      "type": "string|Buffer|TypedArray|DataView",
                      "desc": "The bytes to decode."
                    }
                  ]
                }
              ],
              "desc": "<p>Returns any remaining input stored in the internal buffer as a string. Bytes\nrepresenting incomplete UTF-8 and UTF-16 characters will be replaced with\nsubstitution characters appropriate for the character encoding.</p>\n<p>If the <code>buffer</code> argument is provided, one final call to <code>stringDecoder.write()</code>\nis performed before returning the remaining input.\nAfter <code>end()</code> is called, the <code>stringDecoder</code> object can be reused for new input.</p>"
            },
            {
              "textRaw": "`stringDecoder.write(buffer)`",
              "type": "method",
              "name": "write",
              "meta": {
                "added": [
                  "v0.1.99"
                ],
                "changes": [
                  {
                    "version": "v8.0.0",
                    "pr-url": "https://github.com/nodejs/node/pull/9618",
                    "description": "Each invalid character is now replaced by a single replacement character instead of one for each individual byte."
                  }
                ]
              },
              "signatures": [
                {
                  "return": {
                    "textRaw": "Returns: {string}",
                    "name": "return",
                    "type": "string"
                  },
                  "params": [
                    {
                      "textRaw": "`buffer` {string|Buffer|TypedArray|DataView} The bytes to decode.",
                      "name": "buffer",
                      "type": "string|Buffer|TypedArray|DataView",
                      "desc": "The bytes to decode."
                    }
                  ]
                }
              ],
              "desc": "<p>Returns a decoded string, ensuring that any incomplete multibyte characters at\nthe end of the <code>Buffer</code>, or <code>TypedArray</code>, or <code>DataView</code> are omitted from the\nreturned string and stored in an internal buffer for the next call to\n<code>stringDecoder.write()</code> or <code>stringDecoder.end()</code>.</p>"
            }
          ],
          "signatures": [
            {
              "params": [
                {
                  "textRaw": "`encoding` {string} The character [encoding][] the `StringDecoder` will use. **Default:** `'utf8'`.",
                  "name": "encoding",
                  "type": "string",
                  "default": "`'utf8'`",
                  "desc": "The character [encoding][] the `StringDecoder` will use."
                }
              ],
              "desc": "<p>Creates a new <code>StringDecoder</code> instance.</p>"
            }
          ]
        }
      ],
      "type": "module",
      "displayName": "String decoder"
    }
  ]
}