Ask the question you just answered in SQL, this time in Mango. A document carries the same formula string, and $regex is the selector’s pattern match: it matches anywhere unless anchored, so no wildcard is written. Return the name and the formula, sorted by name. A sort needs its field in the selector as well, because CouchDB and PouchDB refuse to sort on a field the selector does not mention. The same thirty compounds come back.
A beginner exercise, answered in Mango. It is marked by the rows your query returns rather than by how you wrote it, with 3 hints if you want them.
Ask the same question of a chemical dataset in SQL and in Mango and compare the two answers. The database is a SQLite file your browser downloads once and queries locally, so nothing you write ever leaves your machine — which is also why the tool needs JavaScript.