$lookup on object array with table - node.js

Question

I have data object that contains array. And I have providers table.
if array's Id should equals to provider's table id Id == id
if id is repeated take the repeated count as membersCounts else membersCounts = 0
Add the membersCounts with data object
data object
const data = {
Milk: [
{
Id: 1,
name: 'a'
},
{
Id: 2,
name: 'b'
},
{
Id: 3,
name: 'c'
},
{
Id: 4,
name: 'd'
},
{
Id: 52,
name: 'e'
}
],
Grocery: [
{
Id: 8,
name: '2a'
},
{
Id: 22,
name: '2b'
},
{
Id: 32,
name: '2c'
},
{
Id: 42,
name: '2d'
}
]
}
providers table
const providers = [
{
id: 1,
status: 'active'
},
{
id: 1,
status: 'active'
},
{
id: 1,
status: 'active'
},
{
id: 1,
status: 'active'
},
{
id: 4,
status: 'active'
},
{
id: 2,
status: 'active'
},
{
id: 3,
status: 'active'
},
{
id: 3,
status: 'active'
},
{
id: 52,
status: 'active'
},
{
id: 1,
status: 'active'
}
]
here javascript code
this code is working good but I want perform this with mongodb queries. So that performance is good .
Is possible to do with mongodb query. I need to covert the javascript code to mongodb query.
getMembersWithVendors(data, providers) {
for (var key in data) {
var arr = data[key]
arr.forEach((element) => {
element.memberCounts = 0
element.new = true
providers.map((el) => {
if (element._id == el.vendorId) {
(element.memberCounts = element.memberCounts + 1),
(element.new = false)
}
})
})
}
return data
}
output
{ Milk:
[ { Id: 1, name: 'a', memberCounts: 5 },
{ Id: 2, name: 'b', memberCounts: 1 },
{ Id: 3, name: 'c', memberCounts: 2 },
{ Id: 4, name: 'd', memberCounts: 1 },
{ Id: 52, name: 'e', memberCounts: 1 } ],
Grocery:
[ { Id: 8, name: '2a', memberCounts: 0 },
{ Id: 22, name: '2b', memberCounts: 0 },
{ Id: 32, name: '2c', memberCounts: 0 },
{ Id: 42, name: '2d', memberCounts: 0 } ] }
Thanks !!

Answer 1

this code is working good but I want perform this with mongodb queries. So that performance is good
That is not good idea to do all the operations in query, it may cause performance issues, because your input data is so big, but you can improve some things,
$group by query id and get count, this will return unique ids and its total counts
let providers = await db.providers.aggregate([
{
$group: {
_id: "$id",
count: { $sum: 1 }
}
}
]);
iterate loop of object's array
find from providers on the base of id
get count from filtered document
for (let key in data) {
data[key].forEach(e => {
let p = providers.find(p => p._id === e.Id);
e.memberCounts = p ? p.count : 0;
})
}
console.log(data);
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