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

An abstract-leveldown compliant store on top of IndexedDB.
https://github.com/Level/level-js

abstract-leveldown browser indexeddb level levelup

Last synced: about 1 month ago
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An abstract-leveldown compliant store on top of IndexedDB.

Host: GitHub
URL: https://github.com/Level/level-js
Owner: Level
License: mit
Created: 2013-04-30T04:42:48.000Z (over 11 years ago)
Default Branch: master
Last Pushed: 2023-06-01T09:57:51.000Z (over 1 year ago)
Last Synced: 2024-10-30T00:00:36.257Z (about 1 month ago)
Topics: abstract-leveldown, browser, indexeddb, level, levelup
Language: JavaScript
Homepage:
Size: 274 KB
Stars: 543
Watchers: 16
Forks: 44
Open Issues: 1
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE

Awesome Lists containing this project

awesome-starred - Level/level-js - An abstract-leveldown compliant store on top of IndexedDB. (others)

README

        # level-js

**An [`abstract-leveldown`][abstract-leveldown] compliant store on top of [IndexedDB][indexeddb].**

> :pushpin: This module will soon be [deprecated](https://github.com/Level/community/issues/113), because it is superseded by [`browser-level`](https://github.com/Level/browser-level).

[![level badge][level-badge]][awesome]

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

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

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

[![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)

## Table of Contents

Click to expand

- [Background](#background)

- [Example](#example)

- [Browser Support](#browser-support)

- [Type Support](#type-support)

- [Install](#install)

- [API](#api)

  - [`db = leveljs(location[, options])`](#db--leveljslocation-options)

    - [`options`](#options)

- [Big Thanks](#big-thanks)

- [Contributing](#contributing)

- [Donate](#donate)

- [License](#license)

## Background

Here are the goals of `level-js`:

- Store large amounts of data in modern browsers

- Pass the full [`abstract-leveldown`][abstract-leveldown] test suite

- Support string and [`Buffer`][buffer] keys and values

- Be as fast as possible

- ~~Sync with [multilevel](https://github.com/juliangruber/multilevel) over ASCII or binary transports.~~

Being `abstract-leveldown` compliant means you can use many of the [Level modules][awesome] on top of this library.

## Example

**If you are upgrading:** please see [UPGRADING.md](UPGRADING.md).

```js

const levelup = require('levelup')

const leveljs = require('level-js')

const db = levelup(leveljs('bigdata'))

db.put('hello', Buffer.from('world'), function (err) {

  if (err) throw err

  db.get('hello', function (err, value) {

    if (err) throw err

    console.log(value.toString()) // 'world'

  })

})

```

With `async/await`:

```js

const levelup = require('levelup')

const leveljs = require('level-js')

const db = levelup(leveljs('bigdata'))

await db.put('hello', Buffer.from('world'))

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

```

## Browser Support

[![Sauce Test Status](https://app.saucelabs.com/browser-matrix/level-js.svg)](https://app.saucelabs.com/u/level-js)

## Type Support

Keys and values can be a string or [`Buffer`][buffer]. Any other type will be irreversibly stringified. The only exceptions are `null` and `undefined`. Keys and values of that type are rejected.

In order to sort string and Buffer keys the same way, for compatibility with `leveldown` and the larger ecosystem, `level-js` internally converts keys and values to binary before passing them to IndexedDB.

If you desire non-destructive encoding (e.g. to store and retrieve numbers as-is), wrap `level-js` with [`encoding-down`][encoding-down]. Alternatively install [`level`][level] which conveniently bundles [`levelup`][levelup], `level-js` and `encoding-down`. Such an approach is also recommended if you want to achieve universal (isomorphic) behavior. For example, you could have [`leveldown`][leveldown] in a backend and `level-js` in the frontend. The `level` package does exactly that.

When getting or iterating keys and values, regardless of the type with which they were stored, keys and values will return as a Buffer unless the `asBuffer`, `keyAsBuffer` or `valueAsBuffer` options are set, in which case strings are returned. Setting these options is not needed when `level-js` is wrapped with `encoding-down`, which determines the optimal return type by the chosen encoding.

```js

db.get('key', { asBuffer: false })

db.iterator({ keyAsBuffer: false, valueAsBuffer: false })

```

## Install

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

```bash

npm install level-js

```

Not to be confused with [leveljs](https://www.npmjs.com/package/leveljs).

This library is best used with [browserify](http://browserify.org).

## API

### `db = leveljs(location[, options])`

Returns a new `leveljs` instance. `location` is the string name of the [`IDBDatabase`](https://developer.mozilla.org/en-US/docs/Web/API/IDBDatabase) to be opened, as well as the object store within that database. The database name will be prefixed with `options.prefix`.

#### `options`

The optional `options` argument may contain:

- `prefix` _(string, default: `'level-js-'`)_: Prefix for `IDBDatabase` name.

- `version` _(string | number, default: `1`)_: The version to open the database with.

See [`IDBFactory#open`](https://developer.mozilla.org/en-US/docs/Web/API/IDBFactory/open) for more details.

## Big Thanks

Cross-browser Testing Platform and Open Source ♥ Provided by [Sauce Labs](https://saucelabs.com).

[![Sauce Labs logo](./sauce-labs.svg)](https://saucelabs.com)

## Contributing

[`Level/level-js`](https://github.com/Level/level-js) 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.

## Donate

Support us with a monthly donation on [Open Collective](https://opencollective.com/level) and help us continue our work.

## License

[MIT](LICENSE)

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

[indexeddb]: https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_API

[buffer]: https://nodejs.org/api/buffer.html

[awesome]: https://github.com/Level/awesome

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

[levelup]: https://github.com/Level/levelup

[leveldown]: https://github.com/Level/leveldown

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

[encoding-down]: https://github.com/Level/encoding-down