在JavaScript中使用地图功能

问题描述

我的json响应结构:

My json response structure:

[
    {
        "id": 14,
        "groupname": "Angular",
        "createdAt": "2017-12-15T15:06:39.000Z",
        "updatedAt": "2017-12-15T15:06:39.000Z",
        "contactgroups": [
            {
                "id": 1,
                "contact": {
                    "id": 20,
                    "gsm": "123456789"
                }
            },
            {
                "id": 2,
                "contact": {
                    "id": 21,
                    "gsm": "987654321"
                }
            }
        ]
    },
    {
        "id": 15,
        "groupname": "React",
        "createdAt": "2017-12-15T15:06:45.000Z",
        "updatedAt": "2017-12-15T15:06:45.000Z",
        "contactgroups": [
            {
                "id": 3,
                "contact": {
                    "id": 21,
                    "gsm": "987654321"
                }
            }
        ]
    },
    {
        "id": 16,
        "groupname": "Vue",
        "createdAt": "2017-12-15T15:06:51.000Z",
        "updatedAt": "2017-12-15T15:06:51.000Z",
        "contactgroups": []
    },
    {
        "id": 17,
        "groupname": "NodeJs",
        "createdAt": "2017-12-17T16:07:38.000Z",
        "updatedAt": "2017-12-17T16:07:38.000Z",
        "contactgroups": []
    },
    {
        "id": 18,
        "groupname": "RxJS",
        "createdAt": "2017-12-21T05:50:50.000Z",
        "updatedAt": "2017-12-21T05:50:50.000Z",
        "contactgroups": []
    }
]

我在contactgroups数组中有两个对象，因此我需要将contactsCount返回为2，

i have two objects inside contactgroups array, so i need to return contactsCount as 2,

如果我在contactgroups中有一个对象，我需要将contactsCount返回为1，是否可以使用Javascript中的 map 方法?

if i have one object inside contactgroups i need to return contactsCount as 1, is it possible to do with map method in Javascript?

我想要像这样的最终输出

I want final output like

[
    {
        "id": 14,
        "groupname": "Angular",
        "createdAt": "2017-12-15T15:06:39.000Z",
        "updatedAt": "2017-12-15T15:06:39.000Z",
        "contactsCount: 2,
        "contactgroups": [
            {
                "id": 1,
                "contact": {
                    "id": 20,
                    "gsm": "123456789"
                }
            },
            {
                "id": 2,
                "contact": {
                    "id": 21,
                    "gsm": "987654321"
                }
            }
        ]
    },
    {
        "id": 15,
        "groupname": "React",
        "createdAt": "2017-12-15T15:06:45.000Z",
        "updatedAt": "2017-12-15T15:06:45.000Z",
        "contactsCount: 1,
        "contactgroups": [
            {
                "id": 3,
                "contact": {
                    "id": 21,
                    "gsm": "987654321"
                }
            }
        ]
    },
    {
        "id": 16,
        "groupname": "Vue",
        "createdAt": "2017-12-15T15:06:51.000Z",
        "updatedAt": "2017-12-15T15:06:51.000Z",
        "contactsCount: 0,
        "contactgroups": []
    },
    {
        "id": 17,
        "groupname": "NodeJs",
        "createdAt": "2017-12-17T16:07:38.000Z",
        "updatedAt": "2017-12-17T16:07:38.000Z",
        "contactsCount: 0,
        "contactgroups": []
    },
    {
        "id": 18,
        "groupname": "RxJS",
        "createdAt": "2017-12-21T05:50:50.000Z",
        "updatedAt": "2017-12-21T05:50:50.000Z",
        "contactsCount: 0,
        "contactgroups": []
    }
]

现在看，我的最终输出中包含contactsCount.

see now i have contactsCount inside my final output.

这是我的api代码:

exports.getNewGroupForProfsms = (req, res) => {
    Group.findAll({
        include: [{
            model: ContactGroup,
            attributes: ['id'],
            include: [{
                model: Contact,
                attributes: ['id', 'gsm']
            }]
        }],
    }).then(data => {
        // i am getting json here// how to do map here?
        return res.status(200).send(data);
    }).catch(err => {
        return res.status(400).send(err.message);
    });
};

推荐答案

最后，这个对我有用:

exports.getNewGroupForProfsms = (req, res) => {
  Group.findAll({
    include: [{
      model: ContactGroup,
      attributes: ['id'],
      include: [{
        model: Contact,
        attributes: ['id', 'gsm']
      }]
    }],
  }).then(data => {
    // change happen here
    return res.status(200).send(data.map((x) => {
      // assign contactsCount to each row
      return Object.assign({
        contactsCount: x.contactgroups.length,
      }, x.toJSON()) // update toJSON have a try
    }));
  }).catch(err => {
    return res.status(400).send(err.message);
  });
};

这篇关于在JavaScript中使用地图功能的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！