Question: I want to convert ObjectID (Mongodb) to String in JavaScript.
When I get a Object form MongoDB. it like as a object has: timestamp, second, inc, machine.
I can't convert to string.

Answer: 
Documentation of v4 (right now it's latest version) MongoDB NodeJS Driver says: Method toHexString() of ObjectId returns the ObjectId id as a 24 character hex string representation.
You could use `String`

```
String(a['_id'])

```