lowdb

# lowdb [![](http://img.shields.io/npm/dm/lowdb.svg?style=flat)](https://www.npmjs.org/package/lowdb) [![Node.js CI](https://github.com/typicode/lowdb/actions/workflows/node.js.yml/badge.svg)](https://github.com/typicode/lowdb/actions/workflows/node.js.yml)

> Simple to use type-safe local JSON database 🦉
> 
> If you know JavaScript, you know how to use lowdb.

Read or create `db.json`

```js
const db = await JSONFilePreset('db.json', { posts: [] })
```

Use plain JavaScript to change data

```js
const post = { id: 1, title: 'lowdb is awesome', views: 100 }

// In two steps
db.data.posts.push(post)
await db.write()

// Or in one
await db.update(({ posts }) => posts.push(post))
```

```js
// db.json
{
  "posts": [
    { "id": 1, "title": "lowdb is awesome", "views": 100 }
  ]
}
```

In the same spirit, query using native `Array` functions:

```js
const { posts } = db.data

posts.at(0) // First post
posts.filter((post) => post.title.includes('lowdb')) // Filter by title
posts.find((post) => post.id === 1) // Find by id
posts.toSorted((a, b) => a.views - b.views) // Sort by views
```

It's that simple. `db.data` is just a JavaScript object, no magic.

## Sponsors

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<br>
<br>

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## Features

- **Lightweight**
- **Minimalist**
- **TypeScript**
- **Plain JavaScript**
- Safe atomic writes
- Hackable:
  - Change storage, file format (JSON, YAML, ...) or add encryption via [adapters](#adapters)
  - Extend it with lodash, ramda, ... for super powers!
- Automatically switches to fast in-memory mode during tests

## Install

```sh
npm install lowdb
```

## Usage

_Lowdb is a pure ESM package. If you're having trouble using it in your project, please [read this](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c)._

```js
import { JSONFilePreset } from 'lowdb/node'

// Read or create db.json
const defaultData = { posts: [] }
const db = await JSONFilePreset('db.json', defaultData)

// Update db.json
await db.update(({ posts }) => posts.push('hello world'))

// Alternatively you can call db.write() explicitely later
// to write to db.json
db.data.posts.push('hello world')
await db.write()
```

```js
// db.json
{
  "posts": [ "hello world" ]
}
```

### TypeScript

You can use TypeScript to check your data types.

```ts
type Data = {
  messages: string[]
}

const defaultData: Data = { messages: [] }
const db = await JSONPreset<Data>('db.json', defaultData)

db.data.messages.push('foo') // ✅ Success
db.data.messages.push(1) //