https://github.com/Level/memory-level

In-memory abstract-level database for Node.js and browsers.
https://github.com/Level/memory-level

abstract-level database javascript level memory

Last synced: 9 months ago
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In-memory abstract-level database for Node.js and browsers.

• Host: GitHub
• URL: https://github.com/Level/memory-level
• Owner: Level
• License: mit
• Created: 2022-01-29T19:43:03.000Z (almost 4 years ago)
• Default Branch: main
• Last Pushed: 2024-10-21T22:28:08.000Z (over 1 year ago)
• Last Synced: 2024-10-30T00:00:37.333Z (about 1 year ago)
• Topics: abstract-level, database, javascript, level, memory
• Language: JavaScript
• Homepage:
• Size: 238 KB
• Stars: 28
• Watchers: 7
• Forks: 4
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

          
# memory-level

**In-memory [`abstract-level`][abstract-level] database for Node.js and browsers, backed by a [fully persistent red-black tree](https://www.npmjs.com/package/functional-red-black-tree).** The successor to [`memdown`](https://github.com/Level/memdown) and [`level-mem`](https://github.com/Level/mem).

> :pushpin: Wondering what happened to `levelup`? Visit [Frequently Asked Questions](https://github.com/Level/community#faq).

[![level badge][level-badge]](https://github.com/Level/awesome)

[![npm](https://img.shields.io/npm/v/memory-level.svg)](https://www.npmjs.com/package/memory-level)

[![Node version](https://img.shields.io/node/v/memory-level.svg)](https://www.npmjs.com/package/memory-level)

[![Test](https://img.shields.io/github/actions/workflow/status/Level/memory-level/test.yml?branch=main\&label=test)](https://github.com/Level/memory-level/actions/workflows/test.yml)

[![Coverage](https://img.shields.io/codecov/c/github/Level/memory-level?label=&logo=codecov&logoColor=fff)](https://codecov.io/gh/Level/memory-level)

[![Standard](https://img.shields.io/badge/standard-informational?logo=javascript&logoColor=fff)](https://standardjs.com)

[![Common Changelog](https://common-changelog.org/badge.svg)](https://common-changelog.org)

[![Donate](https://img.shields.io/badge/donate-orange?logo=open-collective&logoColor=fff)](https://opencollective.com/level)

## Usage

_If you are upgrading: please see [`UPGRADING.md`](./UPGRADING.md)._

```js

const { MemoryLevel } = require('memory-level')

// Create a database

const db = new MemoryLevel({ valueEncoding: 'json' })

// Add an entry with key 'a' and value 1

await db.put('a', 1)

// Add multiple entries

await db.batch([{ type: 'put', key: 'b', value: 2 }])

// Get value of key 'a': 1

const value = await db.get('a')

// Iterate entries with keys that are greater than 'a'

for await (const [key, value] of db.iterator({ gt: 'a' })) {

  console.log(value) // 2

}

```

## API

The API of `memory-level` follows that of [`abstract-level`](https://github.com/Level/abstract-level) with one additional constructor option (see below). The `createIfMissing` and `errorIfExists` options of `abstract-level` are not relevant here. Both implicit and explicit snapshots are supported. Data is discarded when the last reference to the database is released (i.e. `db = null`). Closing or reopening the database has no effect on the data. Data is _not_ copied: when storing a Buffer value for example, subsequent mutations to that Buffer will affect the stored data too.

### `db = new MemoryLevel([options])`

Besides `abstract-level` options, the optional `options` object may contain:

- `storeEncoding` (string): one of `'buffer'`, `'view'`, `'utf8'`. How to store data internally. This affects which data types can be stored non-destructively. The default is `'buffer'` (that means Buffer) which is non-destructive. In browsers it may be preferable to use `'view'` (Uint8Array) to be able to exclude the [`buffer`](https://github.com/feross/buffer) shim. Or if there's no need to store binary data, then `'utf8'` (String). Regardless of the `storeEncoding`, `memory-level` supports input that is of any of the aforementioned types, but internally converts it to one type in order to provide a consistent sort order.

## Install

With [npm](https://npmjs.org) do:

```

npm install memory-level

```

## Contributing

[`Level/memory-level`](https://github.com/Level/memory-level) is an **OPEN Open Source Project**. This means that:

> Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project.

See the [Contribution Guide](https://github.com/Level/community/blob/master/CONTRIBUTING.md) for more details.

## License

[MIT](LICENSE)

[abstract-level]: https://github.com/Level/abstract-level

[level-badge]: https://leveljs.org/img/badge.svg