The mapping is not strictly one index per field, but a virtual column expression must map to a MySQL type. So depending on the use-case you may be able to use more complicated expressions to limit indexes.
But to expand your question, there are two FRs we are looking at:
But to expand your question, there are two FRs we are looking at:
1) Inverted (aka FULLTEXT) indexes on JSON documents 2) Multi-value indexes