# blockstore-core

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> Contains various implementations of the API contract described in interface-blockstore

# About

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Various Blockstore implementations are available.

## BaseBlockstore

Provides a complete implementation of the Blockstore interface.  You must implement `.get`, `.put`, etc.

## Example

```js
import { BaseBlockstore } from 'blockstore-core'

class MyCustomBlockstore extends BaseBlockstore {
  put (key, val, options) {
    // store a block
  }

  get (key, options) {
    // retrieve a block
  }

  // ...etc
}
```

## MemoryBlockstore

A simple Blockstore that stores blocks in memory.

## Example

```js
import { MemoryBlockstore } from 'blockstore-core'

const store = new MemoryBlockstore()
```

## BlackHoleBlockstore

A Blockstore that does not store any blocks.

## Example

```js
import { BlackHoleBlockstore } from 'blockstore-core'

const store = new BlackHoleBlockstore()
```

## TieredBlockstore

A tiered blockstore wraps one or more blockstores and will query each in parallel to retrieve a block - the operation will succeed if any wrapped store has the block.

Writes are invoked on all wrapped blockstores.

## Example

```js
import { TieredBlockstore } from 'blockstore-core'

const store = new TieredBlockstore([
  store1,
  store2,
  // ...etc
])
```

## IdentityBlockstore

An identity blockstore is one that deals exclusively in Identity CIDs - this is a special CID with the codec [0x00](https://github.com/multiformats/multicodec/blob/d06fc6194710e8909bac64273c43f16b56ca4c34/table.csv#L2) where the multihash digest is the data that makes up the block.

## Example

```TypeScript
import { IdentityBlockstore } from 'blockstore-core'
import { CID } from 'multiformats/cid'

const blockstore = new IdentityBlockstore()

blockstore.has(CID.parse('QmFoo')) // false

blockstore.has(CID.parse('bafkqac3imvwgy3zao5xxe3de')) // true
```

# Install

```console
$ npm i blockstore-core
```

## Browser `<script>` tag

Loading this module through a script tag will make its exports available as `BlockstoreCore` in the global namespace.

```html
<script src="https://unpkg.com/blockstore-core/dist/index.min.js"></script>
```

# API Docs

- <https://ipfs.github.io/js-stores/modules/blockstore-core.html>

# License

Licensed under either of

- Apache 2.0, ([LICENSE-APACHE](https://github.com/ipfs/js-stores/blob/main/packages/blockstore-core/LICENSE-APACHE) / <http://www.apache.org/licenses/LICENSE-2.0>)
- MIT ([LICENSE-MIT](https://github.com/ipfs/js-stores/blob/main/packages/blockstore-core/LICENSE-MIT) / <http://opensource.org/licenses/MIT>)

# Contribute

Contributions welcome! Please check out [the issues](https://github.com/ipfs/js-stores/issues).

Also see our [contributing document](https://github.com/ipfs/community/blob/master/CONTRIBUTING_JS.md) for more information on how we work, and about contributing in general.

Please be aware that all interactions related to this repo are subject to the IPFS [Code of Conduct](https://github.com/ipfs/community/blob/master/code-of-conduct.md).

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

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