@dishuostec/llrt-types/string_decoder.d.ts

Type definitions for LLRT, Low Latency Runtime

/**
 * 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:
 *
 * ```js
 * const { StringDecoder } = require('string_decoder');
 * ```
 *
 * The following example shows the basic use of the `StringDecoder` class.
 *
 * ```js
 * const { StringDecoder } = require('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: €
 * ```
 *
 * 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:
 *
 * ```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]))); // Prints: €
 * ```
 */
declare module "string_decoder" {
  import { Buffer, BufferEncoding } from "buffer";

  class StringDecoder {
    constructor(encoding?: BufferEncoding);
    /**
     * 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()`.
     * @param buffer The bytes to decode.
     */
    write(buffer: string | Buffer | QuickJS.ArrayBufferView): 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.
     * @param buffer The bytes to decode.
     */
    end(buffer?: string | Buffer | QuickJS.ArrayBufferView): string;
  }
}