Decoding Data

Eclair provides several functions for decoding ABI-encoded data, which can be useful when verifying transactions.

Basic ABI Decoding

The abi.decode function works similarly to Solidity's abi.decode, allowing to decode ABI-encoded data with known types:

>> encoded = abi.encode("Hello", 123)
>> (str, num) = abi.decode(encoded, (string, uint256))
>> str
"Hello"
>> num
123

Decoding Function Call Data

For decoding function calls or error data from contracts, you can use abi.decodeData. This function requires that the relevant contract ABI has been loaded (see Contracts management):

>> dai = ERC20(0x6b175474e89094c44da98b954eedeac495271d0f)
>> data = dai.transfer.encode(0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045, 1e18)
>> abi.decodeData(data)
("transfer(address,uint256)", (0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045, 100000000000000000000))

Note that the output is a tuple and can be manipulated as such:

>> (func, args) = abi.decodeData(data)
>> func
"transfer(address,uint256)"
>> args
(0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045, 1000000000000000000)
>> args[1].format()
"1.00"

Decoding Safe MultiSend Transactions

For decoding Gnosis Safe multiSend transactions, use abi.decodeMultisend:

>> multisendData = 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
>> abi.decodeMultisend(multisendData)
[MultisendTransaction {
    operation: 0,
    to: 0x8A5eB9A5B726583a213c7e4de2403d2DfD42C8a6,
    value: 0,
    data: 0xe2a4853ae060499125866d3940796528a5be3e30632cf5c956aae07e9b72d89c96e053f100000000000000000000000000000000000000000000000006f05b59d3b20000
}, MultisendTransaction {
    operation: 0,
    to: 0x8A5eB9A5B726583a213c7e4de2403d2DfD42C8a6,
    value: 0,
    data: 0xe2a4853a2a55eed44296e96ac21384858860ec77b2c3e06f2d82cbe24bc29993e5a520110000000000000000000000000000000000000000000000000de0b6b3a7640000
}]

Each decoded transaction contains:

• operation: 0 for regular call, 1 for delegatecall
• to: Target address
• value: ETH value in wei
• data: Call data for the transaction

This can be combined with abi.decodeData to decode the data of each transaction. For example:

>> abi.decodeMultisend(multisendData).map((d) >> (d, abi.decodeData(d.data)))
[(MultisendTransaction {
    operation: 0,
    to: 0x8A5eB9A5B726583a213c7e4de2403d2DfD42C8a6,
    value: 0,
    data: 0xe2a4853ae060499125866d3940796528a5be3e30632cf5c956aae07e9b72d89c96e053f100000000000000000000000000000000000000000000000006f05b59d3b20000
}, ("setUint(bytes32,uint256)", (0xe060499125866d3940796528a5be3e30632cf5c956aae07e9b72d89c96e053f1, 500000000000000000))
), (MultisendTransaction {
    operation: 0,
    to: 0x8A5eB9A5B726583a213c7e4de2403d2DfD42C8a6,
    value: 0,
    data: 0xe2a4853a2a55eed44296e96ac21384858860ec77b2c3e06f2d82cbe24bc29993e5a520110000000000000000000000000000000000000000000000000de0b6b3a7640000
}, ("setUint(bytes32,uint256)", (0x2a55eed44296e96ac21384858860ec77b2c3e06f2d82cbe24bc29993e5a52011, 1000000000000000000))
)]