moyan-mongodb-aggregate

npm i moyan-mongodb-aggregate

import {PipelineOptions} from "moyan-mongodb-aggregate";

const pipeline:PipelineOptions = [
    {
        $match:{
            a:'x'
        }
    },
    {
        $lookup:{
            from:'User',
            localField:'user',
            foreignField:'_id',
            as:'user'
        }
    },
    {
        $unwind:{
            path:'$user',
            preserveNullAndEmptyArrays:true
        }
    },
    {
        $group:{
            _id:null,
            total:{
                $sum:1
            }
        }

    }
]