My app will not update the values in the array (Mongoose)

Question

It will update all the values except for the ones in the array, it won't do that .­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­

This is my update

exports.update = function(req, res) {
    if (req.body._id) {
        delete req.body._id;
    }
    plan.findById(req.params.id, function(err, plan) {
        if (err) {
            return handleError(res, err);
        }
        if (!plan) {
            return res.send(404);
        }
        var updated = _.merge(plan, req.body);
        updated.save(function(err) {
            if (err) {
                return handleError(res, err);
            }
            return res.json(200, plan);
        });
    });
};

This is my schema

var ContactSchema = new Schema({
    location: {
        type: String,
        required: true
    },
    total_cost: {
        type: Number,
        required: true
    },
    detailed_expenses: {
        transport: {
            type: String,
            required: true,
            trim: true
        },
        Hotel: {
            type: Number,
            required: true,
            trim: true
        },
        Food: {
            type: Number,
            required: true,
            trim: true
        },
        Attractions: {
            type: Number,
            required: true,
            trim: true
        }
    },
    holiday_type: {
        type: String,
        required: true
    },
    transport_type: {
        type: String,
        required: true
    },
    updated: {
        type: Date,
        default: Date.now
    }
});

Answer 1

var updated = _.merge(plan, req.body);

since updated is simple object not the instance of ContactSchema hence it wont contain save function. So you need to create the instance of ContactSchema using updated then only you can use save function on that. Below is your code with update.

exports.update = function(req, res) {
if (req.body._id) {
    delete req.body._id;
}
plan.findById(req.params.id, function(err, plan) {
    if (err) {
        return handleError(res, err);
    }
    if (!plan) {
        return res.send(404);
    }
    var updated = new plan(req.body); //if req.body is document to be saved
    updated.save(function(err) {
        if (err) {
            return handleError(res, err);
        }
        return res.json(200, plan);
    });
});

};