How to handle ABIs with JavaScript reserved words?

[TrejGun]

Hi guys! I'm working with ERC1155 from OpenZepplin and come across this bug

here is a code of events from OZ
https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC1155/IERC1155.sol#L18-L30

Here are two ways how I get transaction using both ethers and web3

const provider = new ethers.providers.WebSocketProvider(url, options);
const contract = new ethers.Contract(contractAddress, contractInterface, provider);
 contract.on("TransferSingle", data => {
     // do something
 });

const provider = new Web3.providers.WebsocketProvider(url, options);
web3.eth.subscribe("logs", logOptions, (e: Error, raw: Log) => {
    const iface = new ethers.utils.Interface(contractInterface);
    const parsed = iface.parseLog(raw);
});

once I emit TransferSingle it all looks good, the transaction is received and parsed, then I can access all arguments by name

raw tx {
  logIndex: 0,
  removed: false,
  blockNumber: 7312,
  blockHash: '0xbda8de8c4e791730dd9fd05e9ac666f6358625cd990a23642b4d44473ba03867',
  transactionHash: '0x44daf7aa998daf7d6f9dd291a1bf3676f40496f2ed93aa7799de720f79c401dd',
  transactionIndex: 0,
  address: '0x42699A7612A82f1d9C36148af9C77354759b210b',
  data: '0x00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000001',
  topics: [
    '0xc3d58168c5ae7397731d063d5bbf3d657854427343f4c083240f7aacaa2d0f62',
    '0x000000000000000000000000fe3b557e8fb62b89f4916b721be55ceb828dbd73',
    '0x0000000000000000000000000000000000000000000000000000000000000000',
    '0x00000000000000000000000061284003e50b2d7ca2b95f93857abb78a1b0f3ca'
  ],
  id: 'log_cc9a355f'
}

parsed tx LogDescription {
  eventFragment: {
    name: 'TransferSingle',
    anonymous: false,
    inputs: [ [ParamType], [ParamType], [ParamType], [ParamType], [ParamType] ],
    type: 'event',
    _isFragment: true,
    constructor: [Function: EventFragment] {
      from: [Function (anonymous)],
      fromObject: [Function (anonymous)],
      fromString: [Function (anonymous)],
      isEventFragment: [Function (anonymous)]
    },
    format: [Function (anonymous)]
  },
  name: 'TransferSingle',
  signature: 'TransferSingle(address,address,address,uint256,uint256)',
  topic: '0xc3d58168c5ae7397731d063d5bbf3d657854427343f4c083240f7aacaa2d0f62',
  args: [
    '0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73',
    '0x0000000000000000000000000000000000000000',
    '0x61284003E50b2D7cA2B95F93857abB78a1b0F3Ca',
    BigNumber { _hex: '0x01', _isBigNumber: true },
    BigNumber { _hex: '0x01', _isBigNumber: true },
    operator: '0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73',
    from: '0x0000000000000000000000000000000000000000',
    to: '0x61284003E50b2D7cA2B95F93857abB78a1b0F3Ca',
    id: BigNumber { _hex: '0x01', _isBigNumber: true },
    value: BigNumber { _hex: '0x01', _isBigNumber: true }
  ]
}

console.log("ARGS", event.args.operator, event.args.from, event.args.to, event.args.id, event.args.value);

ARGS 0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73 0x0000000000000000000000000000000000000000 0x61284003E50b2D7cA2B95F93857abB78a1b0F3Ca BigNumber { _hex: '0x01', _isBigNumber: true } BigNumber { _hex: '0x01', _isBigNumber: true }

then I do the same with TransferBatch and I can see the transaction, parse it but cant get values from arguments

raw raw {
  logIndex: 0,
  removed: false,
  blockNumber: 8450,
  blockHash: '0x4cdddcba3454fdc4a15a6c5f40ebb23219b949bff9c530e75460ea1f112bc41c',
  transactionHash: '0x16b7f1158604b02ca99b819fef4725af198abdc1326da674478f42fef18f8309',
  transactionIndex: 0,
  address: '0x42699A7612A82f1d9C36148af9C77354759b210b',
  data: '0x000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000001',
  topics: [
    '0x4a39dc06d4c0dbc64b70af90fd698a233a518aa5d07e595d983b8c0526c8f7fb',
    '0x000000000000000000000000fe3b557e8fb62b89f4916b721be55ceb828dbd73',
    '0x0000000000000000000000000000000000000000000000000000000000000000',
    '0x00000000000000000000000061284003e50b2d7ca2b95f93857abb78a1b0f3ca'
  ],
  id: 'log_e8d5fa51'
}

parsed tx LogDescription {
  eventFragment: {
    name: 'TransferBatch',
    anonymous: false,
    inputs: [ [ParamType], [ParamType], [ParamType], [ParamType], [ParamType] ],
    type: 'event',
    _isFragment: true,
    constructor: [Function: EventFragment] {
      from: [Function (anonymous)],
      fromObject: [Function (anonymous)],
      fromString: [Function (anonymous)],
      isEventFragment: [Function (anonymous)]
    },
    format: [Function (anonymous)]
  },
  name: 'TransferBatch',
  signature: 'TransferBatch(address,address,address,uint256[],uint256[])',
  topic: '0x4a39dc06d4c0dbc64b70af90fd698a233a518aa5d07e595d983b8c0526c8f7fb',
  args: [
    '0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73',
    '0x0000000000000000000000000000000000000000',
    '0x61284003E50b2D7cA2B95F93857abB78a1b0F3Ca',
    [ [BigNumber] ],
    [ [BigNumber] ],
    operator: '0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73',
    from: '0x0000000000000000000000000000000000000000',
    to: '0x61284003E50b2D7cA2B95F93857abB78a1b0F3Ca',
    ids: [ [BigNumber] ]
  ]
}

console.log("ARGS", event.args.operator, event.args.from, event.args.to, event.args.ids, event.args.values);

ARGS 0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73 0x0000000000000000000000000000000000000000 0x61284003E50b2D7cA2B95F93857abB78a1b0F3Ca [ BigNumber { _hex: '0x01', _isBigNumber: true } ] [Function: values]

I tried to dig into ethers code but with no luck
what I think might happen is

• ethers create an array of arguments
• then assign named arguments to the array using Object.defineProprties
• for some reason, native function Object.values are not being overridden by argument values
• or vice versa when arguments are being picked by name from transaction object native Object.values is being picked instead of the actual parameter value

Environment:
I use nodejs 16, ethers 5.5.4, web3 1.7.0 on macOS Catalina. Blockchain is Hyperledger Besu

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[ricmoo]

Just a quick look at this issue, I haven’t had time to dig in yet, but based on your comments I suspect it is because you are using property names that conflict with JavaScript built-in names.

There is no way to solve this in JavaScript (especially in v5, which uses only ES3 features). Some of these issues may be mitigated in v6 which use proxies for a lot of these things.

To solve these issues, your best bet is to rename the parameter names in the ABI. The names are not part of the encoded binary, so they are safe to modify.

[TrejGun]

Hi @ricmoo , thanks for the quick reply.

Yes, this is what I suspect, so maybe more properties like freeze and keys are affected

I can't make changes to OpenZepplin :( so have to use another workaround. I'm still able to get value by index event.args[4]

[ricmoo]

Yes, the index access will always work, only keywords will collide, and are not overridden as that can impact the object.

You can still modify the ABI in the OZ contracts if you like, whether it means updating the ABI directly and including it in your code, or spelunking and setting the values yourself in the JSON object (e.g. abi.forEach((c) => { if (c.name === "TheContract") { c.inputs.name = "_values"; } });). I don't think I actually recommend spelunking, but if you needed a quick fix for something.

Thinking about it, perhaps a broader spelunking makes sense:

abi.forEach((f) => {
    f.inputs.forEach((i) => {
        if (i.name === "values") { i.name = "_values"; }
    });
});

But I'm still on the fence about this solution. Indexed access works safely. :)

[TrejGun]

I did not get why did you convert this to the discussion because you basically said this is by design and is not going to be fixed

[ricmoo]

Because others may come across this in the future and it may be useful for them to find here. Issues are more for feature requests and bugs, so discussions also felt more appropriate, and people often don’t search closed issues for their questions.

Also the v6 Result object has additional methods, which can be used to access these keyword-ish values, so I’ll continue the discussion then with details.

[sweeetland]

A bit late to the party here, but Is this just a typo?

In your second log statement, it should be event.args.value not event.args.values i think.

[TrejGun]

sure it is) you can check it in the actual contract