如何使用 web3.js 解码事件中的索引字符串参数？

Question

This is the event -

    event BridgeAdded(
        string indexed tokenTicker,
        string tokenName,
        string imageUrl
    );

I use web3.eth.abi.decodeParameter("string", topics[1]) to decode the indexed string param but get this error -

Error: overflow [ See: https://links.ethers.org/v5-errors-NUMERIC_FAULT-overflow ] (fault="overflow", operation="toNumber", value="105640063387051144792550451261497903460441457163918809975891088748950929433065", code=NUMERIC_FAULT, version=bignumber/5.6.2)
    at Logger.makeError (/home/rajat/bridge-server/node_modules/@ethersproject/logger/lib/index.js:233:21)
    at Logger.throwError (/home/rajat/bridge-server/node_modules/@ethersproject/logger/lib/index.js:242:20)
    at throwFault (/home/rajat/bridge-server/node_modules/@ethersproject/bignumber/lib/bignumber.js:303:19)
    at BigNumber.toNumber (/home/rajat/bridge-server/node_modules/@ethersproject/bignumber/lib/bignumber.js:151:13)
    at /home/rajat/bridge-server/node_modules/@ethersproject/abi/lib/coders/array.js:92:60
    at Array.forEach (<anonymous>)
    at unpack (/home/rajat/bridge-server/node_modules/@ethersproject/abi/lib/coders/array.js:88:12)
    at TupleCoder.decode (/home/rajat/bridge-server/node_modules/@ethersproject/abi/lib/coders/tuple.js:74:60)
    at AbiCoder.decode (/home/rajat/bridge-server/node_modules/@ethersproject/abi/lib/abi-coder.js:98:22)
    at ABICoder.decodeParametersWith (/home/rajat/bridge-server/node_modules/web3-eth-abi/lib/index.js:310:30)
    at ABICoder.decodeParameters (/home/rajat/bridge-server/node_modules/web3-eth-abi/lib/index.js:291:17)
    at ABICoder.decodeParameter (/home/rajat/bridge-server/node_modules/web3-eth-abi/lib/index.js:280:17)
    at populateDb (/home/rajat/bridge-server/eventListener/main.js:140:36)
    at onEvent (/home/rajat/bridge-server/eventListener/main.js:117:19)
    at handleLogs (/home/rajat/bridge-server/eventListener/main.js:90:32)
    at startListening (/home/rajat/bridge-server/eventListener/main.js:64:27) {
  reason: 'overflow',
  code: 'NUMERIC_FAULT',
  fault: 'overflow',
  operation: 'toNumber',
  value: '105640063387051144792550451261497903460441457163918809975891088748950929433065'
}

Please help me resolve this error.

Answer 1

You should use decodeLog instead, and you would also need The ABI byte code in the data field of logs (if you can get the topics array you should get data from logs as well):

let result = web3.eth.abi.decodeLog([{
    type: 'string',
    name: 'tokenTicker',
    indexed: true
    }],
    data,
    topics[1]);