Decode Support

Data processing supports not only encoding (encode) but also decoding (decode). You can use the exchange.IO("decode", types, rawData) function to perform the decode operation.

            javascript
            
            
function main() {
    // register SwapRouter02 abi
    var walletAddress = "0x398a93ca23CBdd2642a07445bCD2b8435e0a373f"
    var routerAddress = "0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45"
    var abi = `[{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactOutputParams","name":"params","type":"tuple"}],"name":"exactOutput","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"}]`
    exchange.IO("abi", routerAddress, abi)   // The abi here contains only part of the content for the exactOutput method; the complete abi can be found online

    // encode path
    var fee = exchange.IO("encodePacked", "uint24", 3000)
    var tokenInAddress = "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
    var tokenOutAddress = "0xdac17f958d2ee523a2206206994597c13d831ec7"
    var path = tokenInAddress.slice(2).toLowerCase()
    path += fee + tokenOutAddress.slice(2).toLowerCase()
    Log("path:", path)

    var dataTuple = {
        "path" : path,
        "recipient" : walletAddress,
        "amountOut" : 1000,
        "amountInMaximum" : 1,
    }
    // encode SwapRouter02 exactOutput
    var rawData = exchange.IO("encode", routerAddress, "exactOutput", dataTuple)
    Log("method hash:", rawData.slice(0, 8))   // 09b81346
    Log("params hash:", rawData.slice(8))

    // decode exactOutput params
    var decodeRaw = exchange.IO("decode", "(bytes,address,uint256,uint256)", rawData.slice(8))
    Log("decodeRaw:", decodeRaw)
}

This example first performs encodePacked encoding on the path parameter, because the exactOutput method call to be encoded subsequently requires path as a parameter. It then performs encode encoding on the exactOutput method of the router contract, which has only one parameter, of type tuple.
The method name exactOutput is encoded as 0x09b81346. Using the exchange.IO("decode", ...) method to decode according to the (bytes,address,uint256,uint256) types yields decodeRaw, whose fields are numbered by position as Field1 through Field4, with each field's value corresponding in order to the contents of the variable dataTuple.