If your application stores and modifies data in MongoDB, you probably use insert and update operations. In certain workflows, you may need to choose between an insert and update depending on whether the document exists.
In these cases, you can streamline your application logic by using the upsert option available in the following methods:
If the query filter passed to these methods does not find any matches and you set the upsert option to true, MongoDB inserts the update document.
Insert or Update in a Single Operation — Node.js. mongodb.com/docs/drivers/node/current/funda...