Koishi In-Memory Database

1.2.0 verified Fri May 01 auth: no javascript

koishi-database-memory is an in-memory database implementation for the Koishi chatbot framework (v4.x). Version 1.2.0 provides a lightweight, zero-configuration database backend that stores all data in memory, suitable for development, testing, or small-scale deployments where persistence is not required. It ships with TypeScript types and requires koishi-core ^1.12.0 as a peer dependency. Unlike SQL-based databases (e.g., koishi-database-sqlite or koishi-database-mysql), it offers the fastest read/write speeds but no data persistence across restarts. The package is maintained as part of the Koishi monorepo and follows its release cadence. It is intended for use cases where temporary storage suffices, and can be easily swapped with a persistent database later.

Common errors

error Error: Cannot find module 'koishi-database-memory' ↓

cause Package not installed or misconfigured in dependencies.

fix

Run 'npm install koishi-database-memory' and ensure it is listed in package.json dependencies.

error TypeError: MemoryDatabase is not a constructor ↓

cause Using `new MemoryDatabase()` instead of `app.plugin(MemoryDatabase)`.

fix

Use app.plugin(MemoryDatabase, options) — do not instantiate directly.

error Error: [cordis] Invalid plugin: Expected function or object but got... ↓

cause MemoryDatabase imported incorrectly (e.g., wrong default import in CommonJS).

fix

Use ESM import syntax: import { MemoryDatabase } from 'koishi-database-memory'.

error TypeError: Cannot read properties of undefined (reading 'extend') ↓

cause MemoryDatabase plugin not installed before calling model methods.

fix

Ensure app.plugin(MemoryDatabase) is called before any database operations.

Warnings

breaking Upgrading from koishi-database-memory v1.0 to v1.2 requires renaming import from 'koishi-plugin-memory' to 'koishi-database-memory'. ↓

fix Replace import { MemoryDatabase } from 'koishi-plugin-memory' with import { MemoryDatabase } from 'koishi-database-memory'.

deprecated Direct use of `new MemoryDatabase()` is deprecated; use `app.plugin(MemoryDatabase, options)` instead. ↓

fix Use the plugin system: app.plugin(MemoryDatabase, {})

gotcha Data is not persisted; all data is lost when the process restarts. ↓

fix Use a persistent database like SQLite or MySQL for production. MemoryDatabase is intended for development/testing.

gotcha MemoryDatabase does not support complex queries like joins or aggregations; it implements only basic CRUD operations. ↓

fix Refer to Koishi database API limitations; use SQL databases for advanced queries.

Install

npm install koishi-database-memory

yarn add koishi-database-memory

pnpm add koishi-database-memory

Imports

MemoryDatabase

wrong

const MemoryDatabase = require('koishi-database-memory')

correct

import { MemoryDatabase } from 'koishi-database-memory'

ESM-only; named export, not default export. TypeScript types are bundled.

default
wrong
```
import { default as MemoryDatabase } from 'koishi-database-memory'
```
correct
```
import MemoryDatabase from 'koishi-database-memory'
```
CommonJS users cannot use require; use ESM with named import instead. Default export is the same as the named export.

type MemoryDatabaseConfig

wrong

import { MemoryDatabaseConfig } from 'koishi-database-memory'

correct

import type { MemoryDatabaseConfig } from 'koishi-database-memory'

Use 'import type' for type-only imports to avoid runtime side effects.

MemoryDatabase

wrong

import MemoryDatabase from 'koishi-database-memory/dist/index.js'

correct

import { MemoryDatabase } from 'koishi-database-memory'

Do not import from dist/; the package exports at the top level.

Quickstart

Shows how to install and use the MemoryDatabase plugin in a Koishi app, including extending a model and creating a record.

import { Context } from 'koishi-core'
import { MemoryDatabase } from 'koishi-database-memory'

const app = new Context()
app.plugin(MemoryDatabase, {})

// Now you can use database operations
app.model.extend('user', {})
app.model.create('user', { name: 'Alice' }).then(user => {
  console.log(user)
})

app.start()