function readEscapeSequence()

in src/worker-lua.js [2330:2387]
39 lines of code
34 McCabe index (conditional complexity)

  function readEscapeSequence() {
    var sequenceStart = index;
    switch (input.charAt(index)) {
      case 'a': ++index; return '\x07';
      case 'n': ++index; return '\n';
      case 'r': ++index; return '\r';
      case 't': ++index; return '\t';
      case 'v': ++index; return '\x0b';
      case 'b': ++index; return '\b';
      case 'f': ++index; return '\f';
      case '\r':
      case '\n':
        consumeEOL();
        return '\n';

      case '0': case '1': case '2': case '3': case '4':
      case '5': case '6': case '7': case '8': case '9':
        while (isDecDigit(input.charCodeAt(index)) && index - sequenceStart < 3) ++index;

        var frag = input.slice(sequenceStart, index);
        var ddd = parseInt(frag, 10);
        if (ddd > 255) {
          raise(null, errors.decimalEscapeTooLarge, '\\' + ddd);
        }
        return encodingMode.encodeByte(ddd, '\\' + frag);

      case 'z':
        if (features.skipWhitespaceEscape) {
          ++index;
          skipWhiteSpace();
          return '';
        }
        break;

      case 'x':
        if (features.hexEscapes) {
          if (isHexDigit(input.charCodeAt(index + 1)) &&
              isHexDigit(input.charCodeAt(index + 2))) {
            index += 3;
            return encodingMode.encodeByte(parseInt(input.slice(sequenceStart + 1, index), 16), '\\' + input.slice(sequenceStart, index));
          }
          raise(null, errors.hexadecimalDigitExpected, '\\' + input.slice(sequenceStart, index + 2));
        }
        break;

      case 'u':
        if (features.unicodeEscapes)
          return readUnicodeEscapeSequence();
        break;

      case '\\': case '"': case "'":
        return input.charAt(index++);
    }

    if (features.strictEscapes)
      raise(null, errors.invalidEscape, '\\' + input.slice(sequenceStart, index + 1));
    return input.charAt(index++);
  }