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nodejs/doc/api/string_decoder.md
foxxyz 6fdd5827f0 doc: anchor link parity between markdown and html-generated docs
Main changes:

- Replace current HTML anchor generation to match
  header anchor generation in Github markdown.
- Remove unnecessary double namespacing on generated anchors/links (E.G.
  `esm.md#loaders` instead of `esm.md#esm_loaders`).
- Anchors/links are automatically prefixed with their respective modules
  when concatenated for usage in `all.html`.

Benefits:

- All anchor links within and between markdown API docs actually work.
- Adding new anchor links no longer requires contributors to generate
  the HTML docs first to look up the correct anchors.
- Anchors are much shorter.
- All previous anchor links are preserved by generating hidden legacy
  anchors.

PR-URL: https://github.com/nodejs/node/pull/39304
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
2021-08-30 00:40:20 +02:00

2.9 KiB

String decoder

Stability: 2 - Stable

The string_decoder module provides an API for decoding Buffer objects into strings in a manner that preserves encoded multi-byte UTF-8 and UTF-16 characters. It can be accessed using:

const { StringDecoder } = require('string_decoder');

The following example shows the basic use of the StringDecoder class.

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));

When a Buffer instance is written to the StringDecoder 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 stringDecoder.write() or until stringDecoder.end() is called.

In the following example, the three UTF-8 encoded bytes of the European Euro symbol () are written over three separate operations:

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])));

Class: StringDecoder

new StringDecoder([encoding])

  • encoding {string} The character encoding the StringDecoder will use. Default: 'utf8'.

Creates a new StringDecoder instance.

stringDecoder.end([buffer])

  • buffer {Buffer|TypedArray|DataView} A Buffer, or TypedArray, or DataView containing the bytes to decode.
  • Returns: {string}

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.

If the buffer argument is provided, one final call to stringDecoder.write() is performed before returning the remaining input. After end() is called, the stringDecoder object can be reused for new input.

stringDecoder.write(buffer)

  • buffer {Buffer|TypedArray|DataView} A Buffer, or TypedArray, or DataView containing the bytes to decode.
  • Returns: {string}

Returns a decoded string, ensuring that any incomplete multibyte characters at the end of the Buffer, or TypedArray, or DataView are omitted from the returned string and stored in an internal buffer for the next call to stringDecoder.write() or stringDecoder.end().