# content-hash

> simple tool to encode/decode content hash for EIP 1577 compliant ENS Resolvers

Latest version **2.5.2** (published 2019-11-19) · ISC license · 0 weekly downloads

## Install

```sh
npm install content-hash
pnpm add content-hash
yarn add content-hash
bun add content-hash
```

## Health

**Score 15/100 (F)** — status: abandoned.

Positive: no vulnerabilities.

Warnings: low downloads; no types; no esm support.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 2.5.2 |
| Published | 2019-11-19 |
| First published | 2018-12-20 |
| Weekly downloads | 0 |
| License | ISC |
| TypeScript types | none |
| Module format | CommonJS |
| Dependencies | 3 |
| Unpacked size | 258.1 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 47 |
| Author | pldespaigne |
| Maintainers | pldespaigne |
| Keywords | ethereum, ens, eip-1577, resolver, ipfs, swarm, content-hash, content, hash, contenthash, contentHash |

## Links

- npm: https://www.npmjs.com/package/content-hash
- Repository: https://github.com/pldespaigne/content-hash
- Homepage: https://github.com/pldespaigne/content-hash#readme
- Issues: https://github.com/pldespaigne/content-hash/issues
- npm.io page: https://npm.io/package/content-hash

## Dependencies (3)

- [cids](https://npm.io/package/cids.md) ^0.7.1
- [multicodec](https://npm.io/package/multicodec.md) ^0.5.5
- [multihashes](https://npm.io/package/multihashes.md) ^0.4.15

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## Recent versions

- 2.5.2 (latest) — 2019-11-19
- 2.5.1 — 2019-11-18
- 2.5.0 — 2019-11-01
- 2.4.4 — 2019-09-17
- 2.4.3 — 2019-07-22
- 2.4.2 — 2019-07-16
- 2.4.1 — 2019-07-15
- 2.3.3 — 2019-07-14
- 2.3.2 — 2019-05-07
- 2.3.1 — 2019-04-27
- 2.4.0 — 2019-01-28
- 2.3.0 — 2019-01-23
- 2.2.0 — 2019-01-22
- 2.1.1 — 2019-01-10
- 2.1.0 — 2019-01-08
- … 10 more at https://npm.io/package/content-hash/versions

## README

# content-hash

[![npm package](https://img.shields.io/npm/v/content-hash.svg)](https://www.npmjs.com/package/content-hash)[![CircleCI](https://circleci.com/gh/pldespaigne/content-hash.svg?style=svg)](https://circleci.com/gh/pldespaigne/content-hash)![licence](https://img.shields.io/npm/l/content-hash.svg)[![Gitter chat](https://badges.gitter.im/content-hash/lobby.png)](https://gitter.im/content-hash/lobby)[![Beerpay](https://beerpay.io/pldespaigne/content-hash/badge.svg)](https://beerpay.io/pldespaigne/content-hash)

>This is a simple package made for encoding and decoding content hashes as specified in the [EIP 1577](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1577.md).
This package will be useful for every [Ethereum](https://www.ethereum.org/) developer wanting to interact with [EIP 1577](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1577.md) compliant [ENS resolvers](http://docs.ens.domains/en/latest/introduction.html).

Here you can find a [live demo](https://content-hash.surge.sh/) of this package.
* link to [npm](https://www.npmjs.com/package/content-hash)
* link to [Github](https://github.com/pldespaigne/content-hash)

## 🔠 Supported Codec
- `swarm-ns`
- `ipfs-ns`
- `ipns-ns`
- Every other codec supported by [multicodec](https://github.com/multiformats/multicodec) will be encoded by default in `utf-8`.
> You can see the full list of codec supported [here](https://github.com/multiformats/multicodec/blob/master/table.csv)

## 📥 Install
* via **npm** :
	```bash
	$> npm install content-hash
	```
* via **Github** : Download or clone this repo, then install the dependencies.
	```bash
	$> git clone https://github.com/pldespaigne/content-hash.git
	$> cd content-hash
	$> npm install
	```
> For browser only usage, installation is not required.

## 🛠 Usage
Import the module in order to use it :
* **NodeJS** :
	```javascript
	const contentHash = require('content-hash')
	```
* **Browser** :
	```html
	<!--From CDN-->
	<script type="text/javascript" src="https://unpkg.com/content-hash/dist/index.js"></script>

	<!--From local module-->
	<script type="text/javascript" src="path/to/dist/index.js"></script>
	```
> To rebuild the browser version of the package run `npm run build` into the root folder. Don't forget to also run `npm run lint` and `npm test` before building !

## 📕 API

> All hex string **inputs** can be prefixed with `0x`, but it's **not mandatory**.

> ⚠️ All **outputs** are **NOT** prefixed with `0x`

### contentHash.decode( contentHash ) -> string
This function takes a content hash as a hex **string** and returns the decoded content as a **string**.
```javascript
const encoded = 'e3010170122029f2d17be6139079dc48696d1f582a8530eb9805b561eda517e22a892c7e3f1f'

const content = contentHash.decode(encoded)
// 'QmRAQB6YaCyidP37UdDnjFY5vQuiBrcqdyoW1CuDgwxkD4'
```

### contentHash.fromIpfs( ipfsHash ) -> string
This function takes an IPFS address as a base58 encoded **string** and returns the encoded content hash as a hex **string**.
> this function just call `contentHash.encode()` under the hood
```javascript
const ipfsHash = 'QmRAQB6YaCyidP37UdDnjFY5vQuiBrcqdyoW1CuDgwxkD4'

const contentH = contentHash.fromIpfs(ipfsHash)
// 'e3010170122029f2d17be6139079dc48696d1f582a8530eb9805b561eda517e22a892c7e3f1f'
```

### contentHash.fromSwarm( swarmHash ) -> string
This function takes a Swarm address as a hex **string** and returns the encoded content hash as a hex **string**.
> this function just call `contentHash.encode()` under the hood
```javascript
const swarmHash = 'd1de9994b4d039f6548d191eb26786769f580809256b4685ef316805265ea162'

const contentH = contentHash.fromSwarm(swarmHash)
// 'e40101701b20d1de9994b4d039f6548d191eb26786769f580809256b4685ef316805265ea162'
```

### contentHash.encode( codec, value) -> string
This function takes a [supported codec](#-supported-codec) as a **string** and a value as a **string** and returns coresponding content hash as a hex **string**.
```javascript
const onion = 'zqktlwi4fecvo6ri'
contentHash.encode('onion', onion);
// 'bc037a716b746c776934666563766f367269'
```

### contentHash.getCodec( contentHash ) -> string
This function takes a content hash as a hex **string** and returns the codec as a hex **string**.
```javascript
const encoded = 'e40101701b20d1de9994b4d039f6548d191eb26786769f580809256b4685ef316805265ea162'

const codec = contentHash.getCodec(encoded) // 'swarm-ns'
codec === 'ipfs-ns' // false
```

### contentHash.helpers
This object contain the following helpers functions :

- #### cidV0ToV1Base32( ipfsHash ) -> string
	This function takes an ipfsHash and convert it to a CID v1 encoded in base32.
	```javascript
	const ipfs = 'QmYwAPJzv5CZsnA625s3Xf2nemtYgPpHdWEz79ojWnPbdG'

	const cidV1 = contentHash.helpers.cidV0ToV1Base32(ipfs)
	// 'bafybeibj6lixxzqtsb45ysdjnupvqkufgdvzqbnvmhw2kf7cfkesy7r7d4'
	```

## 👨‍💻 Maintainer
*  pldespaigne : [github](https://github.com/pldespaigne), [twitter](https://twitter.com/pldespaigne)

## 🙌 Contributing
For any questions, discussions, bug report, or whatever I will be happy to answer through the [issues](https://github.com/pldespaigne/content-hash/issues) or on my [twitter](https://twitter.com/pldespaigne) 😁. PR (with tests) are also welcome !

## 📝 License
This project is licensed under the **ISC License**, you can find it [here](https://github.com/pldespaigne/content-hash/blob/master/LICENSE).
> Note that the dependencies may have a different License

---
_Source: https://npm.io/package/content-hash · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._