mostlydb

MongoDB queries over any storage backend.

mostlydb wraps any unstorage driver with an in-memory cache and MongoDB-style query API. Instead of N network requests per query, documents are loaded once into memory and queried locally using Mingo. Watch-based sync keeps the cache up to date with external changes.

Quick Start

bun add mostlydb

import { createStorage, MostlyDB } from "mostlydb"

const storage = createStorage({ driver: myDriver })
const db = MostlyDB<{ _id: string; name: string; age: number }>(storage, "users:")

// Insert
await db.insertOne({ name: "Alice", age: 30 })

// Query with MongoDB syntax
const adults = await db.find({ age: { $gte: 18 } })
  .sort({ name: 1 })
  .limit(10)
  .toArray()

// Update with operators
await db.updateOne({ name: "Alice" }, { $set: { age: 31 } })

// Delete
await db.deleteMany({ age: { $lt: 18 } })

API Overview

CRUD Operations

| Method | Description | |--------|-------------| | get(key) | Get document by key | | set(key, value) | Set document (infers _id from key) | | del(key) | Delete document by key | | keys(base?) | List keys with optional prefix filter | | insertOne(doc) | Insert document (auto-generates _id) | | updateOne(filter, update) | Update first matching document | | updateMany(filter, update) | Update all matching documents | | deleteOne(filter) | Delete first matching document | | deleteMany(filter) | Delete all matching documents |

Query Operations

| Method | Description | |--------|-------------| | find(query?) | Returns a chainable Cursor | | findOne(query?) | Returns first match or null | | count(query?) | Count matching documents |

Cursor

db.find({ status: "active" })
  .sort({ createdAt: -1 })
  .skip(20)
  .limit(10)
  .toArray()

Update Operators

$set, $unset, $inc, $push, $pull, $addToSet, $pop, $rename

Storage Helpers

• createStorage({ driver }) -- patches getAll from driver for bulk loading
• prefixStorage(storage, prefix) -- namespace isolation with getAll support

Error Handling

StorageWriteError is thrown when backend persistence fails. The cache may be inconsistent -- callers should restart the application.

License

MIT