declare type Location = {
? _normalized?: boolean;
? name?: string;
? path?: string;
? hash?: string;
? query?: Dictionary<string>;
? params?: Dictionary<string>;
? append?: boolean;
? replace?: boolean;
}

declare type RawLocation = string | Location ?//除了是Location類型還可以是字符串

declare type Route = {
? path: string;
? name: ?string;
? hash: string;
? query: Dictionary<string>;
? params: Dictionary<string>;
? fullPath: string;
? matched: Array<RouteRecord>;
? redirectedFrom?: string;
? meta?: any;
}

declare type RouteRecord = {
? path: string;
? regex: RouteRegExp;
? components: Dictionary<any>;
? instances: Dictionary<any>; ? //表示組件的實例 一個對象類型
? name: ?string;
? parent: ?RouteRecord; ?//表示父的 RouteRecord?
? redirect: ?RedirectOption;
? matchAs: ?string;
? beforeEnter: ?NavigationGuard;
? meta: any;
? props: boolean | Object | Function | Dictionary<boolean | Object | Function>;
}

//記錄path 及 path到RouteRecord的映射
if (!pathMap[record.path]) {
? ? pathList.push(record.path) ?// ?['/aaa/bbb','/cccc/ddd']
? ? pathMap[record.path] = record ?//path值作為key?
? ? // ?/aaa/bbb:{ path:"/aaa/bbb" ,regex : //}
}

//記錄name到RouteRecord的映射；  name值作為key
if (name) {
    if (!nameMap[name]) {
      nameMap[name] = record
    } else if (process.env.NODE_ENV !== 'production' && !matchAs) {
      warn(
        false,
        `Duplicate named routes definition: ` +
          `{ name: "${name}", path: "${record.path}" }`
      )
    }
  }

function formatMatch (record: ?RouteRecord): Array<RouteRecord> {
  const res = []
  while (record) {
    res.unshift(record)
    record = record.parent
  }
  return res
}