操作對象里的值

var arr = [
    {
        name:"新聞",
        id:1,
        parent_id: 0,
        child:[
        {
          name:"廣東新聞",
          id:2,
          parent_id: 1,
            child:[
              {
                now: true,
                  name:"深圳新聞",
                  id:4,
                  parent_id: 2
              },{
                now: false,
                  name:"廣州新聞",
                  id:5,
                  parent_id: 2
              }
          ]
        },
        {
          name:"湖南新聞",
          id:3,
          parent_id: 1,
          child:[
            {
              now: true,
              name:"株洲新聞",
              parent_id: 3,
              id:6
            },{
              now: false,
              name:"長沙新聞",
              parent_id: 3,
              id:7
            }
          ]
        }]
      },
      {
        name:"學(xué)院",
        id:8,
        parent_id: 0,
        child:[
        {
          name:"廣東學(xué)院",
          id:9,
          parent_id: 8,
            child:[
              {
                now: true,
                  name: "深圳大學(xué)",
                  id:11,
                  parent_id: 9
              },{
                now: false,
                  name:"中山大學(xué)",
                  id:12,
                  parent_id: 9
              }
          ]
        },
        {
          name:"湖南學(xué)院",
          id:10,
          parent_id: 8,
          child:[
            {
              now: false,
              name:"長沙師范學(xué)院",
              parent_id: 10,
              id:13
            },{
              now: false,
              name:"株洲學(xué)院",
              parent_id: 10,
              id:14
            }
          ]
        }]
      },
    ];

我想獲取數(shù)組的最后級一級如果now為true的話根據(jù)他的parent_id找到他的父級，
然后獲取它以及它父級的id，這樣不斷向上獲取它的父級
最后返回一個(gè)數(shù)組結(jié)果是[1,2,3,4,6,8,9,11]
這樣該怎么查找?