How to implement guide with nested json objects serialization in node.js using express and mongoose
I've searched everywhere and can't find a clear answer. I've looked through the documentation and I'm still confused about I'm stuck on something that should probably be simple... I'm currently working on a Node.js application using Express and Mongoose, and I'm having trouble serializing a nested JSON object that includes a mix of primitive and complex types. When I try to send the object as a JSON response, I receive the behavior `TypeError: Converting circular structure to JSON`. Here's the structure I'm trying to serialize: ```javascript const userSchema = new mongoose.Schema({ name: String, email: String, profile: { age: Number, address: { street: String, city: String, coordinates: { lat: Number, lng: Number, } } } }); const User = mongoose.model('User', userSchema); app.get('/user/:id', async (req, res) => { const user = await User.findById(req.params.id).populate('profile.address'); res.json(user); }); ``` I suspect the `populate` method might be causing a circular reference because the `address` field is being populated with another Mongoose document. I’ve also tried serializing the object manually with `JSON.stringify`, but that didn't resolve the scenario either, as it still throws the same behavior. I've looked at various approaches to handle this, like using the `lean()` method in Mongoose to return plain JavaScript objects instead of Mongoose documents, but I’m not sure if that would work in this scenario without losing some data. Here’s what I tried: ```javascript const user = await User.findById(req.params.id).populate('profile.address').lean(); res.json(user); ``` However, the `lean()` method doesn't seem to fix the scenario, and I still encounter the same behavior message. Any insights on how to properly serialize this nested structure without running into circular references would be greatly appreciated! My development environment is Windows. Has anyone else encountered this? My development environment is Ubuntu. Is there a better approach? I'd be grateful for any help. Thanks for any help you can provide!