This is a drop-in replacement for [LevelDOWN][] that writes to a JSON file on disk.
It also retains the contents of the entire JSON file in memory, so it's only really useful for debugging purposes and/or very small data stores that need just a pinch of persistence.
const levelup = require("levelup");
const jsondown = require("jsondown");
const db = levelup(new jsondown("./mydata.json"));
db.put("foo", "bar");