Mongoose: Find and update an object in an array [duplicate]

I have a Mongoose schema here:

const assetSchema = new mongoose.Schema({
  symbol: String,
  amount: Number
})

const userSchema = new mongoose.Schema({
    user: String,
    budget: Number,
    assets: [assetSchema]
  })

I try to use it to simulate stock trading. I have users in database and their stocks record in an array. Like this:

{
"user": "John", 
"budget": 10000, 
"assets": [{"symbol":"TSLA", "amount": 5}, {"symbol":"AAPL", "amount": 10}, ........ ]
}

How can I find a particular object in assets array by its symbol, and update it? {"symbol":"TSLA", "amount": 20} for example. or how to redesign my schema would be better?