JavaScript Object.hasOwnProperty（）问题

Question

This is a document from mongodb:

{
    "_id" : ObjectId("5c11827eec69860e24519415"),
    "cardNumber" : "4519021475877785",
    "accounts" : [ 
        {        
            "_id" : ObjectId("5c10975d58fdf013e803e5da"),
            "currency" : "CAD"
        }
    ]
}

I get the account from it: account = data.accounts[0] .

I can get the value of currency of this account: currency = account.currency

In my opinion, I think the account in JavaScript is an object.

So, account.hasOwnProperty('currency') should be true .

But it is false when I run my code....

Anyone has idea?

Answer 1

The object Mongoose gives you as the result of your query is not a plain-old JS object. It is a Document object (that class is defined in Mongoose) that holds the data somewhere else (possibly in its prototype chain), which is why hasOwnProperty returns false.

If you want to get your hands on an object that does contain the data fields as own properties, you can call the toObject() method of the Document object. Docs here