How can I list all the records to see if they are duplicated?

Question

I have a problem that I cannot resolve. I have a table in MongoDB, and this is structure:

const shopEconomy = new mongoose.Schema({
    guildID: { type: String },
    name: { type: String },
    value: { type: Number },
    description: { type: String },
    rolereq: { type: String },
    roleadd: { type: String },
    roleremove: { type: String },
    buyinfo: { type: String }
});

I need to list all names from the table (shopData.name) and then check if the typed name exists in the database. I tried to do something like the one below, but it doesn't work.

const shopData = await shopEconomy.find({ guildID: message.guild.id });

        let categories = [];
        let data = new Object();
        for(const i in shopData){
            data += `${shopData[i].name}\n`

            categories.push(data)
        }

Could someone take a look at this and help me out?

score 0 · Answer 1 · answered Apr 15 '22 at 18:19

Part of the issue here comes from the use of a for...in loop which treats shopData as an object and loops over all properties of it. Instead try using a for...of loop which treats shopData as an array and loops over all objects in it.

...

for(const i of shopData) {
    data += `${i.name}\n`

    ...
}

See also this question on for...in vs for...of and this question on JavaScript loops.

Buzz Moschetti · Accepted Answer · 2022-04-15T18:58:46.417

The title of the question does not quite match the description of the question. Given the description, let's assume the typed name is assigned to var typedName.
Let's also assume that you have bound your shopEconomy schema to a model that will actually interact with a mongodb collection called shopData. Then this will iterate all the docs in the shopData:

var found = false;
cursor = db.shopData.find();  // get EVERYTHING
cursor.forEach(function(doc) {
  print(doc['name']);
  if(doc['name'] == typedName) {
    found = true;
  }
});
if(found) {
  print(typedName,"was found");
}

It is likely that the OP wants to find duplicate name in the collection, for which this pipeline will work:

db.shopData.aggregate([
    {$group: {_id: '$name', N:{$sum:1}} },
    {$match: {'N':{$gt:1}}}
]);

How can I list all the records to see if they are duplicated?

2 Answers2