decodeFunctionData

Decodes ABI encoded data (4 byte selector & arguments) into a function name and arguments.

The opposite of encodeFunctionData.

Install

import { decodeFunctionData } from 'viem'

import { decodeFunctionData } from 'viem'

Usage

Below is a very basic example of how to decode a function to calldata.

example.tsabi.tsclient.ts

import { decodeFunctionData } from 'viem'

const { functionName } = decodeFunctionData({
  abi: wagmiAbi,
  data: '0xc2985578'
})
// { functionName: 'totalSupply' }

import { decodeFunctionData } from 'viem'

const { functionName } = decodeFunctionData({
  abi: wagmiAbi,
  data: '0xc2985578'
})
// { functionName: 'totalSupply' }

export const wagmiAbi = [
  ...
  {
    inputs: [],
    name: "totalSupply",
    outputs: [{ name: "", type: "uint256" }],
    stateMutability: "view",
    type: "function",
  },
  ...
] as const;

export const wagmiAbi = [
  ...
  {
    inputs: [],
    name: "totalSupply",
    outputs: [{ name: "", type: "uint256" }],
    stateMutability: "view",
    type: "function",
  },
  ...
] as const;

import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})

import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})

Extracting Arguments

If your calldata includes argument(s) after the 4byte function signature, you can extract them with the args return value.

example.tsabi.tsclient.ts

import { decodeFunctionData } from 'viem'
import { publicClient } from './client'
import { wagmiAbi } from './abi'

const { functionName, args } = decodeFunctionData({
  abi: wagmiAbi,
  data: '0x0423a1320000000000000000000000000000000000000000000000000000000000000001'
})
// { functionName: 'balanceOf', args: [1n] }

import { decodeFunctionData } from 'viem'
import { publicClient } from './client'
import { wagmiAbi } from './abi'

const { functionName, args } = decodeFunctionData({
  abi: wagmiAbi,
  data: '0x0423a1320000000000000000000000000000000000000000000000000000000000000001'
})
// { functionName: 'balanceOf', args: [1n] }

export const wagmiAbi = [
  ...
  {
    inputs: [{ name: "owner", type: "address" }],
    name: "balanceOf",
    outputs: [{ name: "", type: "uint256" }],
    stateMutability: "view",
    type: "function",
  },
  ...
] as const;

export const wagmiAbi = [
  ...
  {
    inputs: [{ name: "owner", type: "address" }],
    name: "balanceOf",
    outputs: [{ name: "", type: "uint256" }],
    stateMutability: "view",
    type: "function",
  },
  ...
] as const;

import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})

import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})

Return Value

{
  functionName: string;
  args: unknown[] | undefined;
}

{
  functionName: string;
  args: unknown[] | undefined;
}

Decoded ABI function data.

functionName

Type: string

The decoded function name.

args

Type: unknown[] | undefined

The decoded function arguments.

Parameters

abi

Type: Abi

The contract's ABI.

const { functionName } = decodeFunctionData({
  abi: wagmiAbi, 
  data: '0xc2985578'
})

const { functionName } = decodeFunctionData({
  abi: wagmiAbi, 
  data: '0xc2985578'
})

data

Type: Hex

The encoded calldata.

const { functionName } = decodeFunctionData({
  abi: wagmiAbi,
  data: '0xc2985578' 
})

const { functionName } = decodeFunctionData({
  abi: wagmiAbi,
  data: '0xc2985578' 
})

decodeFunctionData ​

Install ​

Usage ​

Extracting Arguments ​

Return Value ​

functionName ​

args ​

Parameters ​

abi ​

data ​