位置等级

位置是应用程序可用于与浏览器的 URL 进行交互的服务。根据使用的 LocationStrategy，Location 将持久保存到 URL 的路径或 URL 的哈希段。

Location 负责根据应用程序的基本 href 规范化 URL。

import {Component} from '@angular/core';
import {Location} from '@angular/common';

@Component({
    selector: 'app-component'
})
class AppCmp {

  constructor(_location: Location) {

    //Changes the browsers URL to the normalized version of the given URL, 
    //and pushes a new item onto the platform's history.
    _location.go('/foo');

  }

  backClicked() {
    //Navigates back in the platform's history.
    this._location.back();
  }

  forwardClicked() {
    //Navigates forward in the platform's history.
    this._location.back();
  }
}