🛶 Canoe Solidity

Lightweight Javascript library for decoding constructor arguments.

Summary

Canoe works by reading a contract's ABI and decoding the constructor bytecode with the argument types provided.

Install

npm install canoe-solidity

Requirements

• ABI schema 2.0

Documentation

Functions

decodeConstructorArgs(contractABI, bytecode) ⇒ Object

Decodes constructor args.

encodeConstructorArgs(inputs) ⇒ string

Generates constructor args bytecode based on input data.

decodeFunctionArgs(contractABI, bytecode) ⇒ Object

Decodes function call args.

decodeConstructorArgs(contractABI, bytecode) ⇒ Object

Decodes constructor args.

Kind: global function
Returns: Object - decodedArgs - Object representing decoded args with name, type, and data fields

Param	Type	Description
contractABI	Object	ABI of contract whose args to decode
bytecode	string	Constructor args bytecode

encodeConstructorArgs(inputs) ⇒ string

Generates constructor args bytecode based on input data.

Kind: global function
Returns: string - bytecode - Constructor args bytecode

Param	Type	Description
inputs	Array.<Object>	Array of objects with name, and type fields
inputs[].name	string	Name of argument
inputs[].type	string	Type of argument

decodeFunctionArgs(contractABI, bytecode) ⇒ Object

Decodes function args.

Kind: global function
Returns: Object - decodedArgs - Object representing decoded args with name, type, and data fields

Param	Type	Description
contractABI	Object	ABI of contract whose args to decode
bytecode	string	function args bytecode, methohID included

Supported Types

• bool
• uint
• int
• fixed
• address
• bytes1, bytes2, bytes3, ..., bytes32
• byte
• string
• arrays
• multi-dimensional arrays
• mapping
• struct

Example

const { decodeConstructorArgs } = require('canoe-solidity');
let abiExample = {
  'abi': [
    {
      'anonymous': false,
      'inputs': [
        {
          'name': 'addresses',
          'type': 'address[]',
        },
        {
          'name': 'quantities',
          'type': 'uint256[]',
        },
        {
          'name': '_creationUnit',
          'type': 'uint256',
        },
        {
          'name': '_name',
          'type': 'string',
        },
        {
          'name': '_symbol',
          'type': 'string',
        }
      ],
      'payable': false,
      'stateMutability': 'nonpayable',
      'type': 'constructor'
    }
  ]
};
let bytecodeExample = '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';
decodeConstructorArgs(abiExample.abi, bytecodeExample);

Output:

[
  {
    "name": "addresses",
    "type": "address[]",
    "data": [
      "ffffffffffffffffffffffffffffffffffffffff",
      "f1e48f13768bd8114a530070b43257a63f24bb12"
    ]
  },
  {
    "name": "quantities",
    "type": "uint256[]",
    "data": [
      "5",
      "10"
    ]
  },
  {
    "name": "_creationUnit",
    "type": "uint256",
    "data": "10000000000000000000"
  },
  {
    "name": "_name",
    "type": "string",
    "data": "Ethereum10 Q2-2018"
  },
  {
    "name": "_symbol",
    "type": "string",
    "data": "E10"
  }
]