API to insert data to array of objects in mongoDB - node.js

Question

I am trying to insert array of objects inside array of objects in my mongoDB schema. This is how i want my schema to appear.
const CourseSchema = mongoose.Schema({
categoryname: {
type: String,
required: "Course Category",
min: 3,
max: 100
},
coursename: {
type: String,
required: "Course Name",
min: 3,
max: 100
},
levels:
[
{
levelid: Number,
levelname: String,
chapter:
[
{
chapternumber: Number,
chaptername: String,
content: String //To be elaborated
}
]
}
]
});
My API which i have written looks like this:
exports.addcourse = (req, res) => {
let levels = [];
levels.push({
levelid: req.body.levelid,
levelname: req.body.levelname,
chapter: [
{
chapternumber: req.body.chapternumber,
chaptername: req.body.chaptername,
content: req.body.content
}
]
})
const newCourse = new Course({
coursename: req.body.coursename,
categoryname: req.body.categoryname,
levels: levels
});
newCourse.save(function (error) {
if (error) res.json({ message: 'could not add course because ' + error });
res.json({ newCourse: newCourse });
});
}
This works fine when i enter one level and one chapter, but gives an error when i enter multiple data.
I am giving input from postman 'x-www'form-urlencoded'.
please help.
The error i get when i add one more levelid and levelname in postman
{
"message": "could not add course because ValidationError: levels.0.levelid: Cast to Number failed for value \"[ '1', '2' ]\" at path \"levelid\", levels.0.levelname: Cast to String failed for value \"[ 'First Level', 'Second Level' ]\" at path \"levelname\""
}
The data i am trying to enter

Answer 1

In postman, when you are sending the same key levelid twice, it converts it to array containing both the values. Like in your case, in req.body.levelid, you will receive [1, 2]. But in your schema, levelid is expecting a number value. Also, you are reading it wrong in your API code. Instead of getting levelid and chapter seperately, you can get the levels array in request body with values levelid, levelname and chapter. Similarly, chapter can be an array of objects. req.body.levels will look like this:
[{
levelid: 1,
levelname: "level1",
chapter: [{
chapternumber: 1,
chaptername: "chapter1",
content: "chapter1-content"
}, {
chapternumber: 2,
chaptername: "chapter2",
content: "chapter2-content"
}]
}]
Try this in postman by giving input in raw