如何通过从内部嵌套对象中过滤某些元素来获取新对象

时间：2019-01-22 16:52:33

标签： javascript

我正在尝试通过过滤现有对象来创建对象。 我要实现的目标是过滤内部对象activities并仅获取completed_at以下的所有1546964467值。

我现在尝试的是：

this.weekHabits = this.formattedHabits.filter(habit =>
    habit.activities.map((item) =>({
        activities: item.activities.completed_at.filter(
            value => value = 1546646400
        )
    }))
)

但是显然是错误的

感谢您的耐心等待，我们将不胜感激

这是原始对象：

[
   {
      "frequency":[
         7,
         6,
         2,
         1
      ],
      "description":"Walk 100km",
      "color":"#E97825",
      "activities":[
         {
            "completed":true,
            "completed_at":1546646400
         },
         {
            "completed":true,
            "completed_at":1546819200
         },
         {
            "completed":true,
            "completed_at":1546905600
         },
         {
            "completed":true,
            "completed_at":1547251200
         },
         {
            "completed":false,
            "completed_at":1547424000
         },
         {
            "completed":true,
            "completed_at":1547510400
         },
         {
            "completed":true,
            "completed_at":1547856000
         },
         {
            "completed":false,
            "completed_at":1548028800
         }
      ]
   },
   {
      "frequency":[
         5,
         4,
         3,
         1
      ],
      "description":"Drink 4lt Water",
      "color":"#ED1E24",
      "activities":[
         {
            "completed":true,
            "completed_at":1546387200
         },
         {
            "completed":true,
            "completed_at":1546473600
         },
         {
            "completed":false,
            "completed_at":1546560000
         },
         {
            "completed":false,
            "completed_at":1546819200
         },
         {
            "completed":true,
            "completed_at":1546992000
         },
         {
            "completed":false,
            "completed_at":1547078400
         },
         {
            "completed":false,
            "completed_at":1547164800
         },
         {
            "completed":false,
            "completed_at":1547424000
         },
         {
            "completed":true,
            "completed_at":1547596800
         },
         {
            "completed":false,
            "completed_at":1547683200
         },
         {
            "completed":true,
            "completed_at":1547769600
         },
         {
            "completed":true,
            "completed_at":1548028800
         }
      ]
   },
   {
      "frequency":[
         7,
         6,
         5,
         4,
         3,
         2,
         1
      ],
      "description":"Study 2",
      "color":"#F4ED59",
      "activities":[
         {
            "completed":false,
            "completed_at":1546387200
         },
         {
            "completed":true,
            "completed_at":1546473600
         },
         {
            "completed":true,
            "completed_at":1546560000
         },
         {
            "completed":true,
            "completed_at":1546646400
         },
         {
            "completed":true,
            "completed_at":1546819200
         },
         {
            "completed":false,
            "completed_at":1546905600
         },
         {
            "completed":true,
            "completed_at":1546992000
         },
         {
            "completed":true,
            "completed_at":1547078400
         },
         {
            "completed":false,
            "completed_at":1547164800
         },
         {
            "completed":true,
            "completed_at":1547251200
         },
         {
            "completed":true,
            "completed_at":1547424000
         },
         {
            "completed":false,
            "completed_at":1547510400
         },
         {
            "completed":true,
            "completed_at":1547596800
         },
         {
            "completed":false,
            "completed_at":1547683200
         },
         {
            "completed":true,
            "completed_at":1547769600
         },
         {
            "completed":false,
            "completed_at":1547856000
         },
         {
            "completed":false,
            "completed_at":1548028800
         }
      ]
   },
   {
      "frequency":[
         7,
         6,
         5,
         4
      ],
      "description":"Home drinking food2",
      "color":"#00A651",
      "activities":[
         {
            "completed":true,
            "completed_at":1546473600
         },
         {
            "completed":true,
            "completed_at":1546560000
         },
         {
            "completed":true,
            "completed_at":1546646400
         },
         {
            "completed":true,
            "completed_at":1547078400
         },
         {
            "completed":true,
            "completed_at":1547164800
         },
         {
            "completed":true,
            "completed_at":1547251200
         },
         {
            "completed":false,
            "completed_at":1547683200
         },
         {
            "completed":true,
            "completed_at":1547769600
         },
         {
            "completed":true,
            "completed_at":1547856000
         }
      ]
   },
   {
      "frequency":[
         7,
         4,
         3,
         2,
         1
      ],
      "description":"New habit 4",
      "color":"#912AD6",
      "activities":[
         {
            "completed":true,
            "completed_at":1546387200
         },
         {
            "completed":true,
            "completed_at":1546473600
         },
         {
            "completed":true,
            "completed_at":1546819200
         },
         {
            "completed":true,
            "completed_at":1546905600
         },
         {
            "completed":false,
            "completed_at":1546992000
         },
         {
            "completed":true,
            "completed_at":1547078400
         },
         {
            "completed":false,
            "completed_at":1547424000
         },
         {
            "completed":true,
            "completed_at":1547510400
         },
         {
            "completed":true,
            "completed_at":1547596800
         },
         {
            "completed":true,
            "completed_at":1547683200
         },
         {
            "completed":true,
            "completed_at":1548028800
         }
      ]
   }
]

3 个答案:

答案 0 :(得分：0)

您在代码中遗漏了一些东西。

比较和赋值不是同一回事。此value = 1546646400应该在过滤器中的value <= 1546646400 

let obj = [{"frequency":[7,6,2,1],"description":"Walk 100km","color":"#E97825","activities":[{"completed":true,"completed_at":1546646400},{"completed":true,"completed_at":1546819200},{"completed":true,"completed_at":1546905600},{      "completed":true,"completed_at":1547251200},{          "completed":false,"completed_at":1547424000 },{            "completed":true,"completed_at":1547510400},{            "completed":true,"completed_at":1547856000},{            "completed":false,"completed_at":1548028800}]},{"frequency":[ 5,4,3,1],"description":"Drink 4lt Water","color":"#ED1E24", "activities":[{"completed":true,"completed_at":1546387200},"completed":true,"completed_at":1546473600},"completed":false,"completed_at":1546560000},{"completed":false, "completed_at":1546819200},{"completed":true,"completed_at":1546992000},{"completed":false,"completed_at":1547078400 },{"completed":false, "completed_at":1547164800 },{"completed":false,"completed_at":1547424000},    {"completed":true,"completed_at":1547596800},"completed":false,"completed_at":1547683200},{"completed":true,"completed_at":1547769600},{"completed":true,"completed_at":1548028800}]},{"frequency":[7,6,5,4,3,2,1],"description":"Study 2","color":"#F4ED59","activities":[{"completed":false,"completed_at":1546387200},{"completed":true,"completed_at":1546473600},{"completed":true,"completed_at":1546560000},{"completed":true,"completed_at":1546646400},{"completed":true,"completed_at":1546819200},{"completed":false,"completed_at":1546905600},{"completed":true,"completed_at":1546992000},{"completed":true,"completed_at":1547078400},{"completed":false,"completed_at":1547164800},{"completed":true,"completed_at":1547251200},{"completed":true,"completed_at":1547424000},{"completed":false,"completed_at":1547510400},{"completed":true,"completed_at":1547596800},{"completed":false,"completed_at":1547683200},{"completed":true,"completed_at":1547769600},{"completed":false,"completed_at":1547856000},{"completed":false,"completed_at":1548028800}]},{"frequency":[7,6,5,4],"description":"Home drinking food2","color":"#00A651","activities":[{"completed":true,"completed_at":1546473600},{"completed":true,"completed_at":1546560000},{"completed":true,"completed_at":1546646400},{"completed":true,"completed_at":1547078400},{"completed":true,"completed_at":1547164800},{"completed":true,"completed_at":1547251200},{"completed":false,"completed_at":1547683200},{"completed":true,"completed_at":1547769600},{"completed":true,"completed_at":1547856000}]},{"frequency":[7,4,3,2,1],"description":"New habit 4","color":"#912AD6","activities":[{"completed":true,"completed_at":1546387200},{"completed":true,"completed_at":1546473600},
{
"completed":true,
"completed_at":1546819200},{"completed":true,"completed_at":1546905600},{"completed":false,"completed_at":1546992000},{"completed":true,"completed_at":1547078400},{"completed":false,"completed_at":1547424000},{"completed":true,"completed_at":1547510400},{"completed":true,"completed_at":1547596800},{"completed":true,"completed_at":1547683200},{"completed":true,"completed_at":1548028800}]}]

let op = obj.map(ele=>{
  let {activities} = ele
  let selected = activities.filter(element=> element.completed_at <= 1546646400 )
  return {
    ...ele,
    activities: selected
  }
})

console.log(op)

答案 1 :(得分：0)

我认为（看一下您实现的代码）您想要这样的东西，即保留所有对象结构，但我们过滤activities数组以仅保留那些满足条件{{1 }}：

completed_at <= <some_number>

答案 2 :(得分：0)

您在那儿混合了一些东西，您尝试使用map的响应作为过滤条件，然后您使用的地图应该是过滤器，基本上就是您所做的工作的一部分。 / p>

我认为这就是您想要的：

this.formattedHabits = [{
    "frequency": [
      7,
      6,
      2,
      1
    ],
    "description": "Walk 100km",
    "color": "#E97825",
    "activities": [{
        "completed": true,
        "completed_at": 1546646400
      },
      {
        "completed": true,
        "completed_at": 1546819200
      },
      {
        "completed": true,
        "completed_at": 1546905600
      },
      {
        "completed": true,
        "completed_at": 1547251200
      },
      {
        "completed": false,
        "completed_at": 1547424000
      },
      {
        "completed": true,
        "completed_at": 1547510400
      },
      {
        "completed": true,
        "completed_at": 1547856000
      },
      {
        "completed": false,
        "completed_at": 1548028800
      }
    ]
  },
  {
    "frequency": [
      5,
      4,
      3,
      1
    ],
    "description": "Drink 4lt Water",
    "color": "#ED1E24",
    "activities": [{
        "completed": true,
        "completed_at": 1546387200
      },
      {
        "completed": true,
        "completed_at": 1546473600
      },
      {
        "completed": false,
        "completed_at": 1546560000
      },
      {
        "completed": false,
        "completed_at": 1546819200
      },
      {
        "completed": true,
        "completed_at": 1546992000
      },
      {
        "completed": false,
        "completed_at": 1547078400
      },
      {
        "completed": false,
        "completed_at": 1547164800
      },
      {
        "completed": false,
        "completed_at": 1547424000
      },
      {
        "completed": true,
        "completed_at": 1547596800
      },
      {
        "completed": false,
        "completed_at": 1547683200
      },
      {
        "completed": true,
        "completed_at": 1547769600
      },
      {
        "completed": true,
        "completed_at": 1548028800
      }
    ]
  },
  {
    "frequency": [
      7,
      6,
      5,
      4,
      3,
      2,
      1
    ],
    "description": "Study 2",
    "color": "#F4ED59",
    "activities": [{
        "completed": false,
        "completed_at": 1546387200
      },
      {
        "completed": true,
        "completed_at": 1546473600
      },
      {
        "completed": true,
        "completed_at": 1546560000
      },
      {
        "completed": true,
        "completed_at": 1546646400
      },
      {
        "completed": true,
        "completed_at": 1546819200
      },
      {
        "completed": false,
        "completed_at": 1546905600
      },
      {
        "completed": true,
        "completed_at": 1546992000
      },
      {
        "completed": true,
        "completed_at": 1547078400
      },
      {
        "completed": false,
        "completed_at": 1547164800
      },
      {
        "completed": true,
        "completed_at": 1547251200
      },
      {
        "completed": true,
        "completed_at": 1547424000
      },
      {
        "completed": false,
        "completed_at": 1547510400
      },
      {
        "completed": true,
        "completed_at": 1547596800
      },
      {
        "completed": false,
        "completed_at": 1547683200
      },
      {
        "completed": true,
        "completed_at": 1547769600
      },
      {
        "completed": false,
        "completed_at": 1547856000
      },
      {
        "completed": false,
        "completed_at": 1548028800
      }
    ]
  },
  {
    "frequency": [
      7,
      6,
      5,
      4
    ],
    "description": "Home drinking food2",
    "color": "#00A651",
    "activities": [{
        "completed": true,
        "completed_at": 1546473600
      },
      {
        "completed": true,
        "completed_at": 1546560000
      },
      {
        "completed": true,
        "completed_at": 1546646400
      },
      {
        "completed": true,
        "completed_at": 1547078400
      },
      {
        "completed": true,
        "completed_at": 1547164800
      },
      {
        "completed": true,
        "completed_at": 1547251200
      },
      {
        "completed": false,
        "completed_at": 1547683200
      },
      {
        "completed": true,
        "completed_at": 1547769600
      },
      {
        "completed": true,
        "completed_at": 1547856000
      }
    ]
  },
  {
    "frequency": [
      7,
      4,
      3,
      2,
      1
    ],
    "description": "New habit 4",
    "color": "#912AD6",
    "activities": [{
        "completed": true,
        "completed_at": 1546387200
      },
      {
        "completed": true,
        "completed_at": 1546473600
      },
      {
        "completed": true,
        "completed_at": 1546819200
      },
      {
        "completed": true,
        "completed_at": 1546905600
      },
      {
        "completed": false,
        "completed_at": 1546992000
      },
      {
        "completed": true,
        "completed_at": 1547078400
      },
      {
        "completed": false,
        "completed_at": 1547424000
      },
      {
        "completed": true,
        "completed_at": 1547510400
      },
      {
        "completed": true,
        "completed_at": 1547596800
      },
      {
        "completed": true,
        "completed_at": 1547683200
      },
      {
        "completed": true,
        "completed_at": 1548028800
      }
    ]
  }
]

this.weekHabits = this.formattedHabits.map(habit =>
  habit.activities.filter(item => item.completed_at <= 1546964467)
)


console.log(this.weekHabits)

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