Add or update with db.js

A common question with db.js is how to merge data from a remote store into the local store. When doing so you need to think about how you’re handling an add vs an update statement. Say you have some records that you’re syncing between the two instances and they have a common key that you use to identify on both the client and the server. When a user hits the site you pull down the records and want to work out if they are to be inserted or just updated against what you already have.