Question

我正在尝试返回item内的所有数组项，这是我的数组：

    var data =  [
      {
        "id": 275,
        "nome": "name",
        "item": [
          {
            "idCentro": 2,
            "date": "2018-06-05",
            "tipo": "D"
          },
          {
            "idCentro": 6,
            "date": "2017-06-05",
            "tipo": "G"
          },
          {
            "idCentro": 18,
            "date": "2016-06-05",
            "tipo": "G"
          },
          {
            "idCentro": 29,
            "date": "2019-06-05",
            "tipo": "D"
          }
        ]
      }
    ]

因此，要在item内获取所有项目，但它不起作用：

let listaT = data.filter(item => {
  return{
    idCentro: item.item.idCentro,
    date: item.item.date,
    tipo: item.item.tipo,
  }
})

我想得到这种回报：

[
  {
    "idCentro": 2,
    "date": "2018-06-05",
    "tipo": "D"
  },
  {
    "idCentroCusto": 6,
    "date": "2017-06-05",
    "tipo": "G"
  },
  {
    "idCentroCusto": 18,
    "date": "2016-06-05",
    "tipo": "G"
  },
  {
    "idCentroCusto": 29,
    "date": "2019-06-05",
    "tipo": "D"
  }
]

我该如何实现？

Answer 1

如果只想获取项目数组，则只需要

var array = data[0].item

Answer 2

您可以展平所有项目数组。

 var data =  [{ id: 275, nome: "name", item: [{ idCentro: 2, date: "2018-06-05", tipo: "D" }, { idCentro: 6, date: "2017-06-05", tipo: "G" }, { idCentro: 18, date: "2016-06-05", tipo: "G" }, { idCentro: 29, date: "2019-06-05", tipo: "D" }] }],
    result = data.reduce((r, { item }) => [...r, ...item], []);

console.log(result);

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或者采用即将到来的Array#flatMap。

 var data =  [{ id: 275, nome: "name", item: [{ idCentro: 2, date: "2018-06-05", tipo: "D" }, { idCentro: 6, date: "2017-06-05", tipo: "G" }, { idCentro: 18, date: "2016-06-05", tipo: "G" }, { idCentro: 29, date: "2019-06-05", tipo: "D" }] }],
    result = data.flatMap(({ item }) => item);

console.log(result);

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Answer 3

Array.prototype.filter()方法创建一个新数组，其中所有元素都通过了由提供的函数实现的测试。它不会修改数组项。

您可以使用Array.prototype.map()和Array.prototype.flat()

var data =  [
      {
        "id": 275,
        "nome": "name",
        "item": [
          {
            "idCentro": 2,
            "date": "2018-06-05",
            "tipo": "D"
          },
          {
            "idCentro": 6,
            "date": "2017-06-05",
            "tipo": "G"
          },
          {
            "idCentro": 18,
            "date": "2016-06-05",
            "tipo": "G"
          },
          {
            "idCentro": 29,
            "date": "2019-06-05",
            "tipo": "D"
          }
        ]
      }
    ]


let listaT = data.map(({item}) => item).flat();
console.log(listaT);

Answer 4

将Array#reduce与Array#concat一起使用。这也使用destructuring assignment。

reduce（）方法在数组的每个成员上执行reducer函数（由您提供），从而产生单个输出值。

const data=[{"id":275,"nome":"name","item":[{"idCentro":2,"date":"2018-06-05","tipo":"D"},{"idCentro":6,"date":"2017-06-05","tipo":"G"},{"idCentro":18,"date":"2016-06-05","tipo":"G"},{"idCentro":29,"date":"2019-06-05","tipo":"D"}]}]
    
 const res = data.reduce((a, {item}) => a.concat(item), []);
 
 console.log(res);

如何返回对象数组内的所有项目

4 个答案: