You can use the following syntax to list all field names in a collection in MongoDB:
Object.keys(db.myCollection.findOne())
This particular example lists every field name in a collection titled myCollection.
The following example shows how to use this syntax in practice with a collection teams with the following documents:
db.teams.insertOne({team: "Mavs", points: 30, rebounds: 8, assists: 2})
db.teams.insertOne({team: "Mavs", points: 35, rebounds: 12, assists: 6})
db.teams.insertOne({team: "Spurs", points: 20, rebounds: 7, assists: 8})
db.teams.insertOne({team: "Spurs", points: 25, rebounds: 5, assists: 9})
db.teams.insertOne({team: "Spurs", points: 23, rebounds: 9, assists: 4})
Example: List All Field Names in MongoDB
The following code shows how to list all field names in the teams collection:
Object.keys(db.teams.findOne())
This query returns the following documents:
[ '_id', 'team', 'points', 'rebounds', 'assists' ]
Notice that the list of field names also includes the _id field, which MongoDB automatically generates for each document.
Note: To list the field names in another collection, simply change the teams name to another name.
Additional Resources
The following tutorials explain how to perform other common operations in MongoDB:
MongoDB: How to Rename Fields
MongoDB: How to Remove Fields
MongoDB: How to Add New Fields