JAVASCRIPT

query in express mongoose

//controllers/tourController.js
const Tour = require('./../models/tourModel');
exports.getAllTours = async (req, res) => {
  try {
    const queryObj = { ...req.query };
    const excludeFields = ['page', 'sort', 'limit', 'fields'];
    excludeFields.forEach((el) => delete queryObj[el]);

    //build a query
    const query = Tour.find(queryObj);
    //execute query
    const tours = await query;

    res.status(200).json({
      status: 'sucess',
      results: tours.length,
      data: {
        tours,
      },
    });
  } catch (error) {
    res.status(404).json({
      status: 'fail',
      message: error,
    });
  }
};

mongoose Query object

model.find({}) instanceof mongoose.Query //true
model.find({}).lean() instanceof mongoose.Query //true

mongoose query document

1.
model.updateOne(
   { <array>: value ... },
   { <update operator>: { "<array>.$" : value } }
)
db.students.updateOne(
   { _id: 4, "grades.grade": 85 },
   { $set: { "grades.$.std" : 6 } }
)