Create compound index with primary key and sort by its items

[dome4]

This PR contains:

A bugfix concerning compound indexes

Describe the problem you have without this PR

I tried to create a compound index (age + id) that contains the primary key (id) of the schema and sort docs by the attributes of the compound index (see test). This fails with the error message "cannot sort on field(s) 'age' when using the default index". Why is the default index ('_id)' used here, although an appropriate custom index has been defined?

The first problem was that in RxStoragePouchDbClass - prepareQuery() the primary key is changed to '_id' and therefore the new custom index does not match the attribute anymore:

rxdb/src/rx-storage-pouchdb.ts

Line 221 in 8b954b4

const useKey = key === primPath ? '_id' : key;

Therefore in my opinion the method createIndex() of RxCollection has to be adapted and the change of the primary key has to be done as well.

Second, the order of the attributes in sort() is changed. This has proven to be a problem with the util sortObject(). When the method is called recursively, the param noArraySort is currently not passed to further calls, which results in nested arrays being sorted. The problem occurred in the method toString() of RxQuery, so the custom index was not found. Additionally, the test typeof obj === 'object' in the method is not sufficient to exclude an array. Therefore I have added !Array.isArray(obj) here.

Hopefully I explained the problem sufficiently :)

Todos

• Changelog

[pubkey]

@dome4 great work, merged.