how to remove a value from an array in database using nodejs and mongoose

Question

I'm trying to remove a value from an array in my database which I get from url.

I use the code below but I get nothing. It doesn't go to the for loop.

app.get('/remove/:medid/:tokenid', function(req, res) {
    var medid = req.params.medid;
    var token = req.params.tokenid;
    var query = { tokenid: token, mediaid !== 'undefined' && mediaid.length > 0 }

    user.find(query).exec(function(err, result) {

        if (err) {
            res.send('erooooooor')
        }
        if (!result) {
            res.send('whooops, you dont have any media yet :)')
        } else {
            console.log('its here')
            for (var i in result.mediaid) {
                console.log(i)
                if (i == medid) {
                    user.update({ tokenid: token }, { $pull: { mediaid: medid } }, function(err, result2) {
                        if (err) {
                            res.send('an error happened')
                        } else {
                            console.log('deleted')
                                //res.send('your tokenid  is '+ token)
                        }
                    })
                } else {
                    res.send('media id didnt match')
                }
            }
        }

    });
});

My database has 3 objects userid and tokenid which are strings and mediaid which is an array.

Also, I want to check if my mediaid array is null or not and exist is this code

mediaid !== 'undefined' && mediaid.length > 0

d_shiv · Accepted Answer · 2016-07-06 19:40:59Z

2

You have got your json syntax incorrect in following line

var query = {tokenid: token, mediaid !== 'undefined' && mediaid.length > 0}

You should probably just let your query be based on token id.

var query = {tokenid: token};

Also when you write for(var i in result.mediaid), for each iteration of loop, the variable 'i' is assigned the index of current element, not its value. So your if condition should be modified to check result.mediaid[i] == medid instead of i == medid. Modified loop should look something like:

for(var i in  result.mediaid){
    console.log(i);
    if(result.mediaid[i] === medid){
        user.update({tokenid: token}, {$pull: {mediaid: medid}},function(err, result2){
        if (err){
            res.send('an error happened');
        }
        else{
            console.log('deleted');
            //res.send('your tokenid  is '+ token)
            }
        });
    }
}

answered Jul 6, 2016 at 19:40

d_shiv

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7 Comments

Shahrzad A Over a year ago

thanks for answering me, but it makes no difference! u see that console.log(i) after for?? when i run it i doesnt appear in command prompt!!

d_shiv Over a year ago

then possibly no mediaid(s) have been saved in DB. If result.mediaid is an empty array, the loop won't be executed at all. You can verify this by querying your mongodb manually from a terminal.

Shahrzad A Over a year ago

no I checked. my database is ok. and if its empty doesnt it go to this part? if(!result)??

d_shiv Over a year ago

Not really. if(!result) part will only be executed if result itself was not returned. You could may be extend that condition if(!result || !result.mediaid || result.mediaid.length < 0), this should give you a better view of your result. You can also try printing the entire result variable for debugging.

Shahrzad A Over a year ago

oh thanks for this valuable information. i printed the result and its like this: [{_id: sth, userid: 'sth', mediaid: ['sth','sth2'], tokenid: 'sth'}]. why is it inside a bracket? and the result.mediaid is undefined?? what is going on?? sorry im a total beginer :)

|

Jose Carlos Ramos Carmenates · Accepted Answer · 2016-07-06 19:39:39Z

0

Please, you can replace to:

app.get('/remove/:mediaid/:tokenid', function(req, res){
var medid = req.params.mediaid;
var token = req.params.tokenid;
var query = {tokenid: token, mediaid !== 'undefined' && mediaid.length > 0}

UPDATED:

I recommended that print after console.log(medid, token);

I hoped help you - Jose Carlos Ramos

answered Jul 6, 2016 at 19:39

Jose Carlos Ramos Carmenates

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3 Comments

Shahrzad A Over a year ago

thanks but i cant see any changes? what did you change?

Jose Carlos Ramos Carmenates Over a year ago

@ShahrzadA mediaid <=> medid

Shahrzad A Over a year ago

yeah i got that but still doesnt work!! it wont go to the for loop!!

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