code: function getFilePath(isModule, id, options) {
      try {
          return resolve.sync(id, options)
      } catch (_err) {
          if (isModule) {
              return null
          }
          return path.resolve(options.basedir, id)
      }
  }
docs: Resolve the given id to file paths.
  @param {boolean} isModule The flag which indicates this id is a module.
  @param {string} id The id to resolve.
  @param {object} options The options of node-resolve module.
  It requires `options.basedir`.
  @returns {string|null} The resolved path.