Method constructor

lib/internal/encoding.js:430–462

(encoding = 'utf-8', options = kEmptyObject)

class TextDecoder {
  constructor(encoding = 'utf-8', options = kEmptyObject) {
    encoding = `${encoding}`;
    validateObject(options, 'options', kValidateObjectAllowObjectsAndNull);

    const enc = getEncodingFromLabel(encoding);
    if (enc === undefined)
      throw new ERR_ENCODING_NOT_SUPPORTED(encoding);

    let flags = 0;
    if (options !== null) {
      flags |= options.fatal ? CONVERTER_FLAGS_FATAL : 0;
      flags |= options.ignoreBOM ? CONVERTER_FLAGS_IGNORE_BOM : 0;
    }

    this[kDecoder] = true;
    this[kFlags] = flags;
    this[kEncoding] = enc;
    this[kIgnoreBOM] = Boolean(options?.ignoreBOM);
    this[kFatal] = Boolean(options?.fatal);
    this[kUTF8FastPath] = false;
    this[kHandle] = undefined;
    this[kSingleByte] = undefined; // Does not care about streaming or BOM
    this[kChunk] = null; // A copy of previous streaming tail or null

    if (enc === 'utf-8') {
      this[kUTF8FastPath] = true;
      this[kBOMSeen] = false;
    } else if (isSinglebyteEncoding(enc)) {
      this[kSingleByte] = createSinglebyteDecoder(enc, this[kFatal]);
    } else {
      this.#prepareConverter(); // Need to throw early if we don't support the encoding
    }
  }

  #prepareConverter() {
    if (hasIntl) {