I need help with sorting in Express working with mongooose db. When i use sort({'price':1}) everythink is good, but when i pass JSON.stringify(sort) which contains and logs out {"price":1} it stops working. Any ideas why?

     if(req.query.sortOption){
    const str = req.query.sortOption.split(':');
    sort[str[0]] = str[1] === 'desc' ? -1:1;
  }


  console.log(JSON.stringify(sort));
//here logs out {"price":-1} which works when i pass it into sort function as a string

  try {
    const annoucements = await Annoucement.find(query)
      .skip(page * annoucementsPerPage)
      .limit(annoucementsPerPage)
      .populate('author')
      .sort(JSON.stringify(sort))
    res.status(200).json({
      status: 'Successfully got an annoucement',
      results: annoucements.length,
      data: {
        annoucements,
      },
    });
  } catch (error) {
    res.status(500).json({
      status: 'Failed to get all annoucements',
      message: error,
    });
  }
};

CodePudding user response：

How to sort in mongoose?

.sort() takes in an object, and does not take in a string. You used JSON.stringify(sort), which made the sort query into a string, hence mongoose could not parse it.

CodePudding user response：

Solution: You should just pass .sort(sort) instead of transforming the object to a string.

Explanation:

Mongoose either accepts

• a string like "price" (for ascending order) or "-price" (for descending order).
• an array (not applicable in this case)
• an object, where the key is the property name and the value is the order (1, "asc", "ascending" or -1, '"desc", "descending"`)

What you did was basically pass the string value "{price:-1}" to it, which does not match any of the use cases. Therefore your sorting does not work as expected.