How do I use arrays of numbers in v6 as bytes?

[ybbus]

Ethers Version

6.6.2

Search Terms

abi types parameter

Describe the Problem

In v5 it was possible to just load an abi definition, and forward all parameters (potentially coming from an api request) to the contract "populate" method.
for example: ["0x1234....", 1, 123, [ ] ]
When the requested types were: [ address, uint256, uint256, bytes ]

In v6 this is not possible anymore since it does not accept the empty array [ ] for the type "bytes".
It seems to be required, that a bytes type is either: string or UInt8Array.

Unfortunately:

• with a string one cannot provide an empty bytes array, since the minimum it accepts is "0x00" that is of course one single byte and is different to "no data". You cannot provide an empty string here to provide "no data".
• a Uint8Array would work, when providing it like: Uint8Array.of(). Then you have an empty array with no data. But this of course cannot be provided via json / apis like that.

--> It would be great, if an untyped array is also accepted and tried to be treated and parsed like an UInt8Array with the from() or of() method.

Otherwise it is not possible without further intervention to provide parameters via json / rest apis directly, without messing with the abi and checking datatypes outside ethers-lib.

Code Snippet

async function main() {
    const abi = `[
    {
        "inputs": [
            {
                "internalType": "address",
                "name": "to",
                "type": "address"
            },
            {
                "internalType": "uint256",
                "name": "tokenId",
                "type": "uint256"
            },
            {
                "internalType": "uint256",
                "name": "amount",
                "type": "uint256"
            },
            {
                "internalType": "bytes",
                "name": "data",
                "type": "bytes"
            }
        ],
        "name": "mint",
        "outputs": [],
        "stateMutability": "payable",
        "type": "function"
    }
]`

    const abiInterface = new Interface(abi)
    const provider = new JsonRpcProvider(
        "http://......",
        {
            name: "MyNetwork",
            chainId: 80001,
        }, {
            staticNetwork: Network.from({
                name: "MyNetwork",
                chainId: 80001,
            })
        }
    )

    const contractAddress: string = "0x1234567"
    const contract = new Contract(contractAddress, abiInterface, provider)

    const contractFunction = contract["mint"]

    const paramsFromJson = [
        "0x0f08462efc7f2f0e0a3e773ca95e2aadee584baf",
        1,
        1,
        []]  // What to put here now in v6?

    const transaction = await contractFunction.populateTransaction(...paramsFromJson)
}

Contract ABI

[
    {
        "inputs": [
            {
                "internalType": "address",
                "name": "to",
                "type": "address"
            },
            {
                "internalType": "uint256",
                "name": "tokenId",
                "type": "uint256"
            },
            {
                "internalType": "uint256",
                "name": "amount",
                "type": "uint256"
            },
            {
                "internalType": "bytes",
                "name": "data",
                "type": "bytes"
            }
        ],
        "name": "mint",
        "outputs": [],
        "stateMutability": "payable",
        "type": "function"
    }
]

Errors

TypeError: invalid BytesLike value (argument="value", value=[  ], code=INVALID_ARGUMENT, version=6.6.2)

Environment

node.js (v12 or newer)

Environment (Other)

No response

[ricmoo]

You should be able to pass in "0x", which is the empty bytes string?

[ybbus]

Hi, indeed that worked. So that seems only array notation is not supported anymore?

[ricmoo]

Yes, array of numbers is no longer supported, as they require a lot more validation and were kinda a nuisance to deal with when trying to deduce types (is it an array of numbers? Is it a tuple of things?).

You can still use them though, by passing them into Uint8Array, like new Uint8Array([ 1, 2, 3 ]), but that doesn’t help your situation with JSON.

Make sense? (Moving to discussions ;))

[ybbus]

Hi. Yes, totally makes sense, for me this behavior is ok and no more need for discussion... Thanks! :)

[ricmoo]

Oh, “discussions” is just a useful place so others in the future with a similar issue can search and find it more easily. :)