Mongodb populate query in nodejs for having condition with populated field - node.js

Question

bellow is my schema's for User, Task and Order. i want to have query which can give me all orders which is assign to particular User.
var User = mongoose.Schema({
firstName : {
type: String,
required: false
},
lastName : {
type: String,
required: false
},
password : {
type: String,
required: false
},
createdAt:{
type: Date,
require: false
},
role:{
type: String,
require: false
}
});
var Task = mongoose.Schema({
assignedOn : {
type:Date
},
assignedTo : {type:mongoose.Schema.Types.ObjectId, ref:'User'},
status : {
type:String
},
priority : {
type: String
},
completeBy:{
type: Date
}
});
var Order = mongoose.Schema({
orderDate:{
type: Date,
require: false
},
completionDate:{
type: Date,
require: false
},
status: {
type: String,
required: false
},
orderType: {
type: String,
required: false
},
remarks: {
type: String,
require: false
},
totalAmount: {
type: Number,
require: false
},
items: {
type: [],
require: true
},
billingAddress: {
type: IAddress,
require: true
},
shippingAddress: {
type: IAddress,
require: true
},
defaultTask: {type:mongoose.Schema.Types.ObjectId, ref:'Task'},
customer: {type:mongoose.Schema.Types.ObjectId, ref:'Customer'}
});
i am doing query like bellow which is not giving me proper result for specific user _id which i want , its giving me all Orders.
this._orderRepository.findAndPopulate({$match:{assignedTo:_id}},
{path:'defaultTask ', populate:{path:'items'}, populate:{path:'assignedTo' }}, function(err, result){
console.log("error =>"+err);
/*console.log("result=>"+result);*/
callback(err, result);
} )