function _readString()

in packages/angular_devkit/core/src/json/parser.ts [322:400]
71 lines of code
25 McCabe index (conditional complexity)

function _readString(context: JsonParserContext, comments = _readBlanks(context)): JsonAstString {
  const start = context.position;

  // Consume the first string delimiter.
  const delim = _token(context);
  if ((context.mode & JsonParseMode.SingleQuotesAllowed) == 0) {
    if (delim == "'") {
      throw new InvalidJsonCharacterException(context);
    }
  }

  let str = '';
  while (true) {
    let char = _token(context);
    if (char == delim) {
      return {
        kind: 'string',
        start,
        end: context.position,
        text: context.original.substring(start.offset, context.position.offset),
        value: str,
        comments: comments,
      };
    } else if (char == '\\') {
      char = _token(context);
      switch (char) {
        case '\\':
        case '/':
        case '"':
        case delim:
          str += char;
          break;

        case 'b':
          str += '\b';
          break;
        case 'f':
          str += '\f';
          break;
        case 'n':
          str += '\n';
          break;
        case 'r':
          str += '\r';
          break;
        case 't':
          str += '\t';
          break;
        case 'u':
          const [c0] = _token(context, '0123456789abcdefABCDEF');
          const [c1] = _token(context, '0123456789abcdefABCDEF');
          const [c2] = _token(context, '0123456789abcdefABCDEF');
          const [c3] = _token(context, '0123456789abcdefABCDEF');
          str += String.fromCharCode(parseInt(c0 + c1 + c2 + c3, 16));
          break;

        case undefined:
          throw new UnexpectedEndOfInputException(context);

        case '\n':
          // Only valid when multiline strings are allowed.
          if ((context.mode & JsonParseMode.MultiLineStringAllowed) == 0) {
            throw new InvalidJsonCharacterException(context);
          }
          str += char;
          break;

        default:
          throw new InvalidJsonCharacterException(context);
      }
    } else if (char === undefined) {
      throw new UnexpectedEndOfInputException(context);
    } else if (char == '\b' || char == '\f' || char == '\n' || char == '\r' || char == '\t') {
      throw new InvalidJsonCharacterException(context);
    } else {
      str += char;
    }
  }
}