检查mongodb文档是否具有架构中未定义的属性？

Question

I am finding a document with mongoose using findOne . I succeded in setting a property, that is not defined in the schema, to the document using doc.set(key, val) . However when I want to check if the document has that property or not, it just shows no even if the document has it.

User.findOne({email: req.user.email})
    .then(user=>{
        if(user.posts){
            //Tried with user.has("posts")=>logs error: .has is not a function
            let posts = user.get("posts");
            posts.push({
                    "Type": "Idea",
                    "Field/s of idea": req.body["Field/s of idea"],
                    "Idea": req.body.idea,
                    "Date": new Date()
                    });
            user.set("posts", posts);
        }else{
            user.set("posts", [{
                    "Type": "Idea",
                    "Field/s of idea": req.body["Field/s of idea"],
                    "Idea": req.body.idea,
                    "Date": new Date()
                    }]
            );
        };
        user.save();
    })
    .catch(err=>{throw err});

Schema code:

const UserSchema = new Schema({
    _id: {type: ObjectId, auto: true},
    username: {type: String, required: true, max:18},
    email: {type: String, required: true},
    password: {type: String, required: true, min:5},
    date_of_registration: {type: Date, required: true}
}, { strict: false });

Answer 1

Schemas are fixed and not dynamic by design. If you are unsure about what type posts will be, add it to your schema and use the Mixed type.

Something like

const UserSchema = new Schema({
    ...
    posts: [ { type: Mixed, required: false } ]
}, { strict: false });