exchange.IO("decode", ...)

解码。

    
    
    
exchange.IO(k, dataFormat, data)

示例

• exchange.IO("encode", ...)函数的反向操作。

  
      javascript
      
      
  function main() {
      // 元组写在圆括号里，字段按位置排列；这里是一个三字段元组，外加一个bytes参数
      var types = "(uint256,uint8,address),bytes"
  
      // 元组的值按位置传数组
      var ret = exchange.IO("encode", types, [30, 20, "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"],
          "0011")
      Log("encode: ", ret)
      // 字面元组没有字段名，按位置编号为Field1、Field2……要用有意义的字段名，
      // 需要先用exchange.IO("abi", ...)注册合约ABI，参考下一个例子
      var rawData = exchange.IO("decode", types, ret)
      Log("decode:", rawData)
  
      // 输出：decode: [{"Field1":"30","Field2":20,"Field3":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"}, "0011"]
  }
  

• 以下例子首先在path参数处理时进行了encodePacked操作，因为之后需要编码的exactOutput方法调用需要path作为参数。然后encode路由合约的exactOutput方法，该方法只有一个参数，参数类型是tuple类型。exactOutput这个方法名编码后即：0x09b81346，使用exchange.IO("decode", ...)方法按(bytes,address,uint256,uint256)解码得出decodeRaw，其字段按位置编号为Field1～Field4，值与变量dataTuple依次对应。

  
      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)   // abi只使用了局部的exactOutput方法的内容，完整的abi可以在网上搜索
  
      // 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))
      // 输出：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)
  }
  

返回值

参数

参考

备注

对于数据的处理，exchange.IO()函数不仅支持编码（encode），也支持解码（decode）。

exchange.IO("unpack", ...)是exchange.IO("decode", ...)的别名。