If you do:

const db = require('level')('db') // or similar
db.approximateSize('a', 'b', { valueEncoding: 'json' }, callback)

Then encoding-down correctly encodes the start (a) and end (b) arguments as JSON, but it also passes the options argument down to leveldown, which doesn't support that: it expects a callback at that index.

Add options to approximateSize() and compactRange() in:

• leveldown
  • PR or commit: pending
  • Release: pending
• rocksdb
  • PR or commit: pending
  • Release: pending
• leveldown-hyper