code: function tryBaseUrlLookUp(info, file, opts) {
    if (root !== baseUrl && info.rest) {
      var ret = findResource(info.rest, baseUrl, opts.extList);
  
      if (ret && ret.file && info.rest[0] === '.') {
        fis.log.warn('Should use `%s` instead of `%s` in [`%s`] since `BaseUrl` should not be used in relative path resolving.', ret.file.subpath, info.rest, file.subpath);
      }
  
      return ret;
    }
  }
docs: 基于 BaseUrl 查找