ethereum-input-to-object

Decodes an Ethereum input data hex string into a developer friendly JavaScript object.

Warning

This package is in alpha, use at your own risk!

Aim

The goal of ethereum-input-to-object is to facilitate dead-simple conversion of a transaction input into a JavaScript native, serializable object.

Usage

Simple example

Pass an ABI and input to inputToObject

import inputToObject from 'ethereum-input-to-object';
const erc20Abi = [{ ... }];
const input = '0xa9059cbb0000000000000000000000005a1cb5a88988ca4fef229935db834a6781e873cb0000000000000000000000000000000000000000000000000de0b6b3a7640000';
const decoded = inputToObject(erc20Abi, input);
console.log(decoded);

{
  methodName: 'transfer',
  params: {
    _to: '0x5A1Cb5A88988cA4FEF229935db834A6781e873cB',
    _value: '1000000000000000000'
  }
}

Unable to decode example

If the input does not match the ABI, inputToObject returns null

import inputToObject from 'ethereum-input-to-object';
const erc20Abi = [{ ... }];
const input = '0xgarbage';
const decoded = inputToObject(erc20Abi, input);
console.log(decoded);

null

Complex example

inputToObject also supports decoding and conversion of complex, nested Solidity data structures.

import inputToObject from 'ethereum-input-to-object';
const setProtocolRebalancingExchangeIssuanceV2Abi = [{ ... }];
const input = '0x16919b9...'; // Truncated for example
const decoded = inputToObject(erc20Abi, input);
console.log(decoded);

{
  methodName: 'issueRebalancingSetWithEther',
  params: {
    _rebalancingSetAddress: '0x81c55017F7Ce6E72451cEd49FF7bAB1e3DF64d0C',
    _rebalancingSetQuantity: '2810697751873000000',
    _exchangeIssuanceParams: {
      setAddress: '0xA37dE6790861B5541b0dAa7d0C0e651F44c6f4D9',
      quantity: '16878240000000000',
      sendTokenExchangeIds: ['1'],
      sendTokens: ['0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2'],
      sendTokenAmounts: ['1874799564199638103'],
      receiveTokens: ['0x89d24A6b4CcB1B6fAA2625fE562bDD9a23260359', '0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599'],
      receiveTokenAmounts: ['121675511211317568000', '1687824'],
    },
    _orderData: '0x000000000000000000000000...', // Truncated for example
    _keepChangeInVault: true,
  }
}

Decoder param example

If you prefer, you may pass a decoder created using ethereum-input-data-decoder instead of an ABI as the first parameter

import InputDataDecoder from 'ethereum-input-data-decoder';
import inputToObject from 'ethereum-input-to-object';
const erc20Abi = [{ ... }];
const erc20Decoder = new InputDataDecoder(erc20Abi);
const input = '0xa9059cbb0000000000000000000000005a1cb5a88988ca4fef229935db834a6781e873cb0000000000000000000000000000000000000000000000000de0b6b3a7640000';
const decoded = inputToObject(erc20Decoder, input);

Usage in node.js

When ES6 imports are not avaliable, you may use require

const inputToObject = require('ethereum-input-to-object')

Supported types

Solidity	JavaScript equivalent used
int (all variations)	String
address	String
string	String
bool	Boolean
bytes (all variations)	String (hex formatted)
tuple	Object (with contents also converted)
array	Array (with contents also converted)

Using a type not supported? Open an issue.

ethereum-input-data-decoder

This library is built on the great work by Miguel on ethereum-input-data-decoder.

If ethereum-input-to-object prioritises convenience over function too much for you, check out his project.