Add another item in array mongodb

Question

I'm inserting a data into an array but when I insert the data, it overwrites the whole array, here is my router for updating array

router.put('/editbloodbankarray', function(req, res) {
        var editUser = req.body._id; 
        var newName = req.body.bloodbank_array; 
        User.findOne({ _id: editUser }, function(err, user) {
            if (err) throw err; 

                user.bloodbank_array = newName; 

                // Save changes
                user.save(function(err) {
                    if (err) {
                        res.json({ success: false, message: 'error' }); 
                    } else {
                        res.json({ success: true, message: 'Name has been updated!' }); 
                    }
                });

        });             
    });

sample document:

_id:5c8521c377df3158d0555db1,
bloodbank_array:
[
0:"1"
1:"2"
]

When I update/insert new item for example: 3..the array turns to:

_id:5c8521c377df3158d0555db1,
bloodbank_array:
[
0:"3"
]

moronator · Accepted Answer · 2019-03-10 16:54:45Z

1

You can use the $push operator to do it directly (look here for more information) but since you already lookup the document first, you could just do user.bloodbank_array.concat(newName); instead of assigning a new value to the array like you do now with user.bloodbank_array = newName. The concat-function is a standard JS-function which inserts a new item at the end of an array. Fore more information you may read the mozilla article.

answered Mar 10, 2019 at 16:54

moronator

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Comments

Buddhabhushan Kamble · Accepted Answer · 2019-03-10 16:54:34Z

0

You are overwriting the existing array. Below is the line

user.bloodbank_array = newName;

Instead do a for loop on the newName array and push the items in user.bloodbank_array like

for(int i=0;i<newName.length;i++)
{
    user.bloodbank_array.push(newName[i]);
}

answered Mar 10, 2019 at 16:54

Buddhabhushan Kamble

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