Dealing with mongodb unique, sparse, compound indexes

Question

Because mongodb will index sparse, compound indexes that contain 1 or more of the indexed fields, it is causing my unique, sparse index to fail because one of those fields

Answer 1

https://docs.mongodb.org/manual/core/index-partial/

As of mongoDB 3.2 you can create partial index to support this as well.

db.users.createIndex(
   { name: 1, email: 1 },
   { unique: true, partialFilterExpression: { email: { $exists: true } } }
)