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https://github.com/mrtenz/eip-712

Tiny library with utility functions that can help with signing and verifying EIP-712 based messages
https://github.com/mrtenz/eip-712

eip712 ethereum signtypeddata

Last synced: 7 days ago
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Tiny library with utility functions that can help with signing and verifying EIP-712 based messages

Host: GitHub
URL: https://github.com/mrtenz/eip-712
Owner: Mrtenz
License: mit
Created: 2020-08-28T13:27:43.000Z (over 4 years ago)
Default Branch: master
Last Pushed: 2024-10-21T17:30:25.000Z (2 months ago)
Last Synced: 2024-10-29T09:53:04.864Z (about 2 months ago)
Topics: eip712, ethereum, signtypeddata
Language: TypeScript
Homepage:
Size: 1.28 MB
Stars: 109
Watchers: 7
Forks: 12
Open Issues: 4
Metadata Files:
- Readme: README.md
- License: LICENSE

Awesome Lists containing this project

README

        # `eip-712`

![Version](https://img.shields.io/npm/v/eip-712) ![License](https://img.shields.io/github/license/Mrtenz/eip-712) [![Actions Status](https://github.com/Mrtenz/eip-712/workflows/CI/badge.svg)](https://github.com/Mrtenz/eip-712/actions) [![codecov](https://codecov.io/gh/Mrtenz/eip-712/branch/master/graph/badge.svg)](https://codecov.io/gh/Mrtenz/eip-712)

This is a library for Node.js and web browsers with some utility functions that can help with signing and verifying [EIP-712](https://eips.ethereum.org/EIPS/eip-712) based messages. It is fully written in TypeScript, and is currently only compatible with the latest specification of EIP-712 ([eth_signTypedData_v4](https://docs.metamask.io/guide/signing-data.html#sign-typed-data-v4)).

https://eips.ethereum.org/EIPS/eip-712

Note that this library currently does not handle the signing itself. For this, you can use something like Ethers.js or ethereumjs-util. For examples, please see the [`examples`](https://github.com/Mrtenz/eip-712/blob/master/examples) folder.

## Installation

You can install this library with Yarn or NPM:

```

$ yarn add eip-712

```

```

$ npm install eip-712

```

There is a CommonJS version as well as an ES6 version available. Most tools should automatically pick the right version (e.g. Node.js, Webpack).

### Getting Started

First, define your typed data as a JSON object, according to the JSON schema specified by EIP-712. For example:

```json

{

  "types": {

    "EIP712Domain": [

      { "name": "name", "type": "string" },

      { "name": "version", "type": "string" },

      { "name": "chainId", "type": "uint256" },

      { "name": "verifyingContract", "type": "address" }

    ],

    "Person": [

      { "name": "name", "type": "string" },

      { "name": "wallet", "type": "address" }

    ],

    "Mail": [

      { "name": "from", "type": "Person" },

      { "name": "to", "type": "Person" },

      { "name": "contents", "type": "string" }

    ]

  },

  "primaryType": "Mail",

  "domain": {

    "name": "Ether Mail",

    "version": "1",

    "chainId": 1,

    "verifyingContract": "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC"

  },

  "message": {

    "from": {

      "name": "Cow",

      "wallet": "0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826"

    },

    "to": {

      "name": "Bob",

      "wallet": "0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB"

    },

    "contents": "Hello, Bob!"

  }

}

```

### Functions

Here is a brief description of the functions available in this library. For more detailed examples, you can refer to [`src/eip-712.test.ts`](https://github.com/Mrtenz/eip-712/blob/master/src/eip-712.test.ts), or to the examples in the [`examples`](https://github.com/Mrtenz/eip-712/blob/master/examples) folder.

#### `getMessage(typedData, hash?)`

This function will return the full EIP-191 encoded message to be signed as Buffer, for the typed data specified. If `hash` is enabled, the message will be hashed using Keccak256.

```js

import { getMessage } from 'eip-712';

const typedData = { /*...*/ };

console.log(getMessage(typedData).toString('hex')); // 1901f2cee375fa42b42143804025fc449deafd50cc031ca257e0b194a650a912090fc52c0ee5d84264471806290a3f2c4cecfc5490626bf912d01f240d7a274b371e

console.log(getMessage(typedData, true).toString('hex')); // be609aee343fb3c4b28e1df9e632fca64fcfaede20f02e86244efddf30957bd2

```

#### `asArray(typedData)`

This function returns the typed data as an array. This can be useful for encoding typed data as ABI.

```js

import { asArray } from 'eip-712';

const typedData = { /*...*/ };

console.log(asArray(typedData)); // [ ['Cow', '0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826'], ['Bob', '0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB'], 'Hello, Bob!' ]

```

#### `getStructHash(typedData, type, data)`

This function returns a Keccak-256 hash for a single struct type (e.g. EIP712Domain, Person or Mail).

```js

import { getStructHash } from 'eip-712';

const typedData = { /*...*/ };

console.log(getStructHash(typedData, 'EIP712Domain', typedData.domain).toString('hex')); // f2cee375fa42b42143804025fc449deafd50cc031ca257e0b194a650a912090f

```

#### `encodeData(typedData, type, data)`

This function returns the raw ABI encoded data for the struct type.

```js

import { encodeData } from 'eip-712';

const typedData = { /*...*/ };

console.log(encodeData(typedData, 'EIP712Domain', typedData.domain).toString('hex')); // 8b73c3c69bb8fe3d512ecc4cf759cc79239f7b179b0ffacaa9a75d522b39400fc70ef06638535b4881fafcac8287e210e3769ff1a8e91f1b95d6246e61e4d3c6c89efdaa54c0f20c7adf612882df0950f5a951637e0307cdcb4c672f298b8bc60000000000000000000000000000000000000000000000000000000000000001000000000000000000000000cccccccccccccccccccccccccccccccccccccccc

```

#### `getTypeHash(typedData, type)`

This function returns the type hash for a struct type. This is the same as `Keccak256(EIP712Domain(string name,string version,uint256 chainId,address verifyingContract))`, with optional sub-types automatically included too.

```js

import { getTypeHash } from 'eip-712';

const typedData = { /*...*/ };

console.log(getTypeHash(typedData, 'EIP712Domain').toString('hex')); // 8b73c3c69bb8fe3d512ecc4cf759cc79239f7b179b0ffacaa9a75d522b39400f

```

#### `encodeType(typedData, type)`

This function returns the type before hashing it, e.g. `EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)`, with optional sub-types automatically included too.

```js

import { encodeType } from 'eip-712';

const typedData = { /*...*/ };

console.log(encodeType(typedData, 'EIP712Domain')); // EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)

```

#### `getDependencies(typedData, type)`

This function returns all sub-types used by a struct as a string array. If the struct has no sub-types (like `EIP712Domain`), an array with only the type itself is returned.

```js

import { getDependencies } from 'eip-712';

const typedData = { /*...*/ };

console.log(getDependencies(typedData, 'EIP712Domain')); // ['EIP712Domain']

console.log(getDependencies(typedData, 'Mail')); // ['Mail', 'Person']

```

### Non-standard domains (e.g., CIP-23)

It's possible to use a custom domain format, like from the CIP-23 specification, or to disable verifying the domain format completely, if you want to use a custom implementation of EIP-712.

To do this, you can pass options to each function, as last parameter. For example, in order to get the message hash for a message, you can do the following:

```ts

import { getMessage } from 'eip-712';

import type { Options } from 'eip-712';

const typedData = { /*...*/ };

const options: Options = {

  // A custom domain identifier. Defaults to 'EIP712Domain'.

  domain: 'CIP23Domain',

  // Whether to verify the structure of the domain. Defaults to 'true'.

  verifyDomain: false

};

console.log(getMessage(typedData, true, options).toString('hex'));

```