Node.js writing api code with mysql(sequelize)

Question

My mysql table models :

//mysql
//table structures start

var Contact = sequelize.define('contact', {
    gsm: {
        type: Sequelize.STRING,
        unique: true,
        required: true
    },
    firstName: Sequelize.STRING,
    lastName: Sequelize.STRING,
    street: Sequelize.STRING,
    city: Sequelize.STRING,
})

var Group = sequelize.define('group', {
    groupname: Sequelize.STRING

})

var ContactGroup = sequelize.define('contactgroup', {
    /* Empty */
})

ContactGroup.belongsTo(Contact, {
    onDelete: 'CASCADE'
});

Contact.hasMany(ContactGroup, {
    onDelete: 'CASCADE'
});

ContactGroup.belongsTo(Group, {
    onDelete: 'CASCADE'
});
Group.hasMany(ContactGroup, {
    onDelete: 'CASCADE'
});

This is my first api code:

exports.getNewGroup = (req, res) => {
    Group.findAll({
        attributes: ['id', 'groupname', [sequelize.fn('COUNT', sequelize.col('contactgroups.groupId')), 'contactsCount']],
        include: [{
            model: ContactGroup,
            attributes: ['id']
        }],
        group: ['id']
    }).then(data => {
        return res.status(200).send(data);
    }).catch(err => {
        return res.status(400).send(err.message);
    });
};

I got the first api response like this:

[
    {
        "id": 14,
        "groupname": "Angular",
        "contactsCount": 2,
        "contactgroups": [
            {
                "id": 1
            }
        ]
    },
    {
        "id": 15,
        "groupname": "React",
        "contactsCount": 1,
        "contactgroups": [
            {
                "id": 3
            }
        ]
    },
    {
        "id": 16,
        "groupname": "Vue",
        "contactsCount": 0,
        "contactgroups": []
    },
    {
        "id": 17,
        "groupname": "NodeJs",
        "contactsCount": 0,
        "contactgroups": []
    },
    {
        "id": 18,
        "groupname": "RxJS",
        "contactsCount": 0,
        "contactgroups": []
    }
]

This is my second api code:

exports.getNewGroupForProfsms = (req, res) => {
    Group.findAll({
        include: [{
            model: ContactGroup,
            attributes: ['id'],
            include: [{
                model: Contact,
                attributes: ['id', 'gsm']
            }]
        }],
    }).then(data => {
        return res.status(200).send(data);
    }).catch(err => {
        return res.status(400).send(err.message);
    });
};

This is my second api response:

[
    {
        "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": "987654321"
                }
            },
            {
                "id": 2,
                "contact": {
                    "id": 21,
                    "gsm": "123456789"
                }
            }
        ]
    },
    {
        "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": "123456789"
                }
            }
        ]
    },
    {
        "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": []
    }
]

In above code, i wrote two apis, now i want to write single api,

I need this type of response: (i have contactsCount in first api response, i want that in second api response)

Finally I want this type of response with single api code:

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

will anyone help me? i need single api code.

I tried nested query, and modified my first api code like this:

exports.getNewGroup = (req, res) => {
    Group.findAll({
        attributes: ['id', 'groupname', [sequelize.fn('COUNT', sequelize.col('contactgroups.groupId')), 'contactsCount']],
        include: [{
            model: ContactGroup,
            attributes: ['id'],
            include: [{
                model: Contact,
                attributes: ['id', 'gsm']
            }]
        }],
        group: ['id']
    }).then(data => {
        return res.status(200).send(data);
    }).catch(err => {
        return res.status(400).send(err.message);
    });
};

But i got this type of response not my requirement

[
    {
        "id": 14,
        "groupname": "Angular",
        "contactsCount": 2,
        "contactgroups": [
            {
                "id": 1,
                "contact": {
                    "id": 20,
                    "gsm": "987654321"
                }
            }
        ]
    },
    {
        "id": 15,
        "groupname": "React",
        "contactsCount": 1,
        "contactgroups": [
            {
                "id": 3,
                "contact": {
                    "id": 21,
                    "gsm": "123456789"
                }
            }
        ]
    },
    {
        "id": 16,
        "groupname": "Vue",
        "contactsCount": 0,
        "contactgroups": []
    },
    {
        "id": 17,
        "groupname": "NodeJs",
        "contactsCount": 0,
        "contactgroups": []
    },
    {
        "id": 18,
        "groupname": "RxJS",
        "contactsCount": 0,
        "contactgroups": []
    }
]

you can nest query group in side first api, or just use `right join` in your sql, but for better performance and design please refer http://docs.sequelizejs.com/manual/tutorial/associations.html#one-to-many-associations-hasmany- — Josh Lin, Dec 21 '17 at 07:47
can you post some piece of code? if i nested query in my first api, i did not got correct response, wait i will post my nested query code which i tried. — Mohamed Sameer, Dec 21 '17 at 08:00
@JoshLin see my updated question, i wrote my nested include code. — Mohamed Sameer, Dec 21 '17 at 08:06
you only want `contactsCount` in second API? something like `res.send(data.map((x)=>{...x,contactsCount:x.contactgroups.length}))`? — Josh Lin, Dec 21 '17 at 08:58
@JoshLin I am new to nodejs, where i can post this code? yes i need only contact count, can you post some answer? — Mohamed Sameer, Dec 21 '17 at 09:01
@Ben i cant able to simplify, but if you read clearly you got my question , if i solve this it will be really helpful to me :) — Mohamed Sameer, Dec 21 '17 at 10:41

Josh Lin · Accepted Answer · 2017-12-21T11:10:26.473

1

try this code

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);
  });
};

edited Dec 21 '17 at 11:10

answered Dec 21 '17 at 09:10

Josh Lin

2,397
11
21

not working, still i dont get contactsCount in my response – Mohamed Sameer Dec 21 '17 at 09:15
i have contactsCount in exports.getnewgroup api. – Mohamed Sameer Dec 21 '17 at 09:16
Still my response looks like https://hastebin.com/irahimuluw.json :) i did not get contactsCount – Mohamed Sameer Dec 21 '17 at 09:22
`Object.assign({ contactsCount: x.contactgroups.length, }, x)` assigned to new object, if it still not working, use `.send(data.map(()=>'aaa'))` to check if response changes – Josh Lin Dec 21 '17 at 09:22
i checked using .send(data.map(()=>'aaa')) . i got [ "aaa", "aaa", "aaa", "aaa", "aaa" ] – Mohamed Sameer Dec 21 '17 at 09:34
i tried your answer: now i am getting like this "Converting circular structure to JSON" in response while checking in POSTMAN – Mohamed Sameer Dec 21 '17 at 09:57
see update `update toJSON have a try` use `toJSON` convert to object, I never used sequelize before, so I'm not sure what will happen – Josh Lin Dec 21 '17 at 11:14
https://stackoverflow.com/questions/47922583/using-map-function-in-javascript/47922649?noredirect=1#comment82814604_47922649 – Mohamed Sameer Dec 21 '17 at 11:15

Node.js writing api code with mysql(sequelize)

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