I need a javascript code that saves in a variable the _id I'm having trouble getting that _id because it’s inside an array.
I have looked everywhere but I can't find a solution for this.
{
"_id": {
"$oid": "626bacea1847f675e47b2bd8"
},
"tipo": "conta",
"data_abertura": {
"$date": "2013-02-19T00:00:00Z"
},
"observacoes": "Sem observações",
"iban": "PT50000506515926456299903",
"saldo": 1456.23,
"bic": "BBPIPTPL001",
"tipo_conta": "Conta Ordenado",
"cartoes": [
{
"_id": {
"$oid": "626bacea1847f675e47b2bd7"
},
"num_cartao": 4908509005925727,
"nome_cartao": "João Correia",
"validade": {
"$date": "2025-10-03T00:00:00Z"
},
"pin": 5609,
"cvc": 975,
"estado": "Ativo",
"tipo_cartao": "Crédito"
}
],
"permissoes": {
"levantamentos": true,
"depositos": true,
"pagamentos": true,
"transferencias": true,
"creditos": true,
"acoes": true
},
"titulares": [
{
"$oid": "626bacea1847f675e47b2bd6"
}
]
}
I want the cartoes _id
"cartoes": [
{
"_id": {
"$oid": "626bacea1847f675e47b2bd7"
},
I want something like this:
let conta = db.banco.findOne({"tipo": "conta"});
idConta = conta._id;
console.log("id: " + idConta);//id: 626bacea1847f675e47b2bd8
Edit:
According to the comments, I understand you want to input num_cartao value and to get an output of the _id of this cartao. You can use an aggregation for this:
const cartao_id = await db.collection.aggregate([
{
$match: {cartoes: {$elemMatch: {"num_cartao": 4908509005925727}}}
},
{
$project: {
cartoes: {
$filter: {
input: "$cartoes",
as: "item",
cond: {$eq: ["$$item.num_cartao", 4908509005925727]}
}
}
}
},
{
$project: {
data: {"$arrayElemAt": ["$cartoes", 0]}
}
},
{
$project: {
_id: {$toString: "$data._id"}
}
}
])
console.log(`cartao_id: ${cartao_id}`);//id: 626bacea1847f675e47b2bd7
That will provide you what you want, as you can see on this playground
You first $match the documents with the right num_cartao, then $filter the right carto from the cartoes array, and then you format it to string.