Where Clause on Compound Index Produces "not indexed" Error

Question

I have the following table schema:

db.version(1).stores({
    sales: "[item_id+date],sales"
});

Where the combination of date and item_id must be unique. How can I get all the records for a given item_id using the where clause (disregarding the date)?

The following produces an error:

db.sales.where('item_id').equals(some_item_id)

Unhandled rejection: SchemaError: KeyPath item_id on object store sales is not indexed

Answer 1

db.sales.where('[item_id+date]').between ([some_item_id, -Infinity], [some_item_id, Dexie.maxKey])