Mongoose 查找不适用于查询 object

Question

I am learning node.js with mongo db . I have a code to fetch records and that works fine

await studentModel.find({}, (err, data) => {
    if (err) throw err;
      students= data.map((d) => {
        return new InterviewQuestion(d['roll_no'], d['name']);
      });
    });

but when I want to filter them then the query doesn't return any record

await studentModel.find({sClass: sClass}, (err, data) => { //sClassis a field in document and also the name of variable
    if (err) throw err;
      students= data.map((d) => {
        return new InterviewQuestion(d['roll_no'], d['name']);
      });
    });

Answer 1

when you use async/await don't use callback and use try/catch in async/await approach so you can do like this

try {
  let data = await studentModel.find({});
  students = data.map((d) => {
    return new InterviewQuestion(d["roll_no"], d["name"]);
  });
} catch (err) {
  throw err;
}

try {
  let data = await studentModel.find({ sClass: sClass });
  students = data.map((d) => {
    return new InterviewQuestion(d["roll_no"], d["name"]);
  });
} catch (err) {
  throw err;
}

this query is correctly

await studentModel.find({ sClass: sClass })

also you can try this:

await studentModel.find({ sClass})

your issue from another thing, because I tested the queries every things is OK

Answer 2

I used a different name for the variable sClass and then it worked. I am still wondering why it is not allowed to have a filter variable with the same name as of document field.