Mongoose save() not updating value in an array in database document

I am trying to update a document in a collection (units) using GUI and after it gets updated I want to update the value (user.Units which is an array of Unit names) in collection (users). If the array length is just 1 element it gets updated and also shows up in database and everything works well, but when Array of Units have more than one element , I try to update it through a for loop, it shows it gets updated but when I check the database it is still not updated.

I really can't figure out why its not updating the database when I update the value through a loop.

**Whole Edit and update function:-**

edit_unit: function (req, res, next) {
var Data = req.body;

Client_data.Unit.findById(req.params.unitId, function (err, unit) {
var error = false;
if (err) {
error = err;
} else if (!unit) {
error = "FATAL: unable to look up Unit #" + req.params.unitId;
} else {

switch(req.body.name) {
case 'Icon':
var Icon = unit.Icon;

User.find({"Units":Icon}, function (err, users) {
if (err)
console.log(err);

users.forEach(function (u) {
if (u.Units.length > 1) {
for (var i = 0; i <= u.Units.length; i++) {
if(u.Units[i] == Icon) {
u.Units[i] = req.body.value;
}
}
}
else {
u.Units = req.body.value;
}
u.save(u);
});
});
unit[req.body.name] = req.body.value;
break;
case 'Description':
unit[req.body.name] = req.body.value;
break;
default:
unit[req.body.name] = req.body.value;
break;
}
var data = JSON.stringify(req.body);
unit.save();

res.writeHead(200, {
'Content-Length': data.length,
'Content-Type': 'application/json'
});
res.end(data);
}
});
}

**req.body:-**


{ name: 'Icon',
value: 'Health Utility 22c',
pk: '5395ed107cd92dc40eaafb56'
}

**User Schema:-**

var userSchema = mongoose.Schema({
UserName: { type: String, required: true },
Password: { type: String },
FirstName: { type: String, required: true },
LastName: { type: String, required: true },
CompanyName: { type: String },
PhoneNumber: { type: Number },
StartDate: { type: Date, required: true },
EndDate: { type: Date, required: true, default: new Date('9999-12-12') },
ClientID: { type: ObjectId, ref: 'Client', default: null },
DepartmentID: { type: ObjectId, ref: 'Department' },
ManagerID: { type: ObjectId, ref: 'User', default: null},
Units: [ { type: String, required: true } ],
UserList: { type: Array, default:[]},
Access: [{ type: String, enum: ['DEMO', 'USER','MANAGER','ADMINISTRATOR','OWNER']}],
Credentials: { type: String },
AFTE: { type: Number},
SessionID: { type: String, default: null }
}, { safe: true });

Refer to [this issue][1]. One way to solve this would be not to update your array via the classic array Index method. So do this

doc.array.set(index, value);

Instead of

doc.array[index] = value;
also view the [FAQ][2] and [doc][3] for more details.


[1]:

[To see links please register here]

[2]:

[To see links please register here]

[3]:

[To see links please register here]

Maybe notify mongooose the dataset has changed like this :

doc.markModified('pathToYourAttribute') 

From the docs [

[To see links please register here]

](

[To see links please register here]

)

person.anything = { x: [3, 4, { y: "changed" }] };
person.markModified('anything');

Hope it helps!

I replaced the save method with this statement:
```
Client_data.Unit.updateOne({_id: unit._id},unit);

yep, I solved this issue by adding doc.markModified('fullName'); etc