Using Map Function In Javascript

My json response structure: [ { 'id': 14, 'groupname': 'Angular', 'createdAt': '2017-12-15T15:06:39.000Z', 'updatedAt': '2017-12-15T15:06:39.00

Solution 1:

You can map the array, and use Object#assign to return a new object with the count:

const arr = [{"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"}}]}];

const result = arr.map((o) =>Object.assign({ contactsCount: o.contactgroups.length || 0 }, o));

console.log(result);

Solution 2:

Use map (or forEach)

data.map( s => ( s.contactsCount = s.contactgroups.length, s ) );

Demo

var data = [
    {
        "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"
                }
            }
        ]
    }
];

data.map( s => ( s.contactsCount = s.contactgroups.length, s ) );

console.log(data);

Solution 3:

// ...    
.then((data) => 
    res.status(200).send(data.map((i) => 
        ((i.contactsCount = i.contactgroups.length), i))))
// ...

...but it is not clear why you want to do this, given that simply retrieving the length of the contactgroups array is trivial.

Solution 4:

You can use data.map(contactgroupcount) like below.

var data =  [
    {
        "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"
                }
            }
        ]
    }
]

    functioncontactgroupcount(obj) {
       obj["contactsCount"] = obj.contactgroups.length;
        return obj;
    }

    data.map(contactgroupcount);

Solution 5:

Finally this one worked for me:

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