Javascript 如何在数组中存储来自另一个json数据的一些数据？

我只想存储给定数组中的续订日期，是否有方法将续订日期存储在另一个数组中。我试过了

const rnDates=[res.result.renewals.renewal_date]；
this.setState（{rn_dates:rnDates}）。

但它显示的是未定义的。如果有人知道如何存储给定对象数组中的特定数据

Object {
      "renewals": Array [
        Object {
          "active_status": "1",
          "added_by": "91",
          "agreement_date": "2020-08-24",
          "contact": "6458766452",
          "created_at": "2020-08-25 10:01:28",
          "email": "Hgg@gmail.com",
          "id": "46",
          "name": "Test4",
          "renewal_date": "2020-08-30",
          "tenure": "Virar",
          "under_user": "91",
        },
        Object {
          "active_status": "1",
          "added_by": "91",
          "agreement_date": "2020-08-24",
          "contact": "6458796454",
          "created_at": "2020-08-24 17:15:21",
          "email": "R@gmail.com",
          "id": "45",
          "name": "Test2 ",
          "renewal_date": "2020-08-30",
          "tenure": "Andheri",
          "under_user": "91",
        },
        Object {
          "active_status": "1",
          "added_by": "91",
          "agreement_date": "2020-08-24",
          "contact": "6465789797",
          "created_at": "2020-08-24 17:14:21",
          "email": "Td@gmail.com",
          "id": "44",
          "name": "Test",
          "renewal_date": "2020-08-30",
          "tenure": "Dahisar",
          "under_user": "91",
        },
        Object {
          "active_status": "1",
          "added_by": "91",
          "agreement_date": "2020-08-24",
          "contact": "6458879767",
          "created_at": "2020-08-24 14:39:27",
          "email": "Om@gmail.com",
          "id": "43",
          "name": "Omkar palace",
          "renewal_date": "2020-08-30",
          "tenure": "Borivali",
          "under_user": "91",
        },
        Object {
          "active_status": "1",
          "added_by": "91",
          "agreement_date": "2020-08-24",
          "contact": "6458766497",
          "created_at": "2020-08-24 11:57:53",
          "email": "Mv@gmail.com",
          "id": "42",
          "name": "Mohak Vila",
          "renewal_date": "2020-08-28",
          "tenure": "Andheri",
          "under_user": "91",
        },
        Object {
          "active_status": "1",
          "added_by": "91",
          "agreement_date": "2020-08-23",
          "contact": "6458799464",
          "created_at": "2020-08-23 12:19:00",
          "email": "Di@gmail.com",
          "id": "41",
          "name": "Sai palace",
          "renewal_date": "2020-08-30",
          "tenure": "Dadar",
          "under_user": "91",
        },
      ],
    }

---

字段

res.result.renewals

是一个对象数组。因此，

res.result.renewals.renewal\u date

未定义

正如其中一条评论所建议的，您需要：

let rnDates = res.result.renewals.map(o => o.renewal_date);

---

从您的问题中不太清楚，但可能

mDates=res.result.renewals.map（o=>o.renewal\u date）？我只想将给定对象的续订日期存储在rn_dates[]的数组名称中，我不想存储所有数据
res.result。续订
是一个对象数组。因此，
res.result.renewals.renewal\u date
未定义。你应该照尼克上面的建议去做。