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decodeFunctionData

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

The opposite of encodeFunctionData.

Install

import { decodeFunctionData } from 'viem'

Usage

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

example.ts
import { decodeFunctionData } from 'viem'
import { wagmiAbi } from './abi.ts'
 
const { functionName } = decodeFunctionData({
  abi: wagmiAbi,
  data: '0x18160ddd'
})
// { functionName: 'totalSupply' }

Extracting Arguments

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

example.ts
import { decodeFunctionData } from 'viem'
import { wagmiAbi } from './abi'
 
const { functionName, args } = decodeFunctionData({
  abi: wagmiAbi,
  data: '0x70a08231000000000000000000000000fba3912ca04dd458c843e2ee08967fc04f3579c2'
})
// { functionName: 'balanceOf', args: ["0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2"] }

Return Value

{
  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

The contract's ABI.

const { functionName } = decodeFunctionData({
  abi: wagmiAbi, 
  data: '0x18160ddd'
})

data

The encoded calldata.

const { functionName } = decodeFunctionData({
  abi: wagmiAbi,
  data: '0x18160ddd'
})