abi.encodeFunctionData <src>

Added in 6.4.0.

This method builds the calldata for a smart contract method: the 4-byte function selector followed by the ABI-encoded parameters. It is the building block behind contract calls, and is useful when you need the raw data field yourself (e.g. to pass to triggerSmartContract / triggerConstantContract, or for an offline transaction).

For just the parameter encoding (without the selector), use abi.encodeParamsV2ByABI.

Usage

tronWeb.utils.abi.encodeFunctionData(funcABI, args);

Parameters

Parameter	Description	Data Type
funcABI	A single function ABI fragment — { type: 'function', name, inputs, outputs? } — not the whole ABI array.	object (FunctionFragment)
args	Optional. The function arguments, in ABI order. Defaults to [].	array

Notes

• Pass one function fragment, not the whole contract ABI array — extract the entry for the method (e.g. abi.find((f) => f.name === 'transfer')).
• The returned hex string has no 0x prefix.
• args.length must equal funcABI.inputs.length, otherwise it throws Invalid arguments provided: expected N arguments, got M.
• A non-function fragment (or one without a name) throws Invalid function ABI fragment provided: only "function" type fragments with a name are supported.
• TRON's trcToken is kept in the selector signature (TVM convention) but encoded as uint256 in the parameters. Base58 addresses inside args are converted to hex automatically.

Returns

hex string - The calldata: selector (8 hex chars) + ABI-encoded parameters, without a 0x prefix.

Example

// transfer(address,uint256)
const funcABI = {
  name: 'transfer',
  type: 'function',
  inputs: [
    { name: 'to', type: 'address' },
    { name: 'amount', type: 'uint256' },
  ],
  outputs: [],
};
const data = tronWeb.utils.abi.encodeFunctionData(funcABI, ['TMVQGm1qAQYVdetCeGRRkTWYYrLXuHK2HC', 100]);
'a9059cbb0000000000000000000000007e5f4552091a69125d5dfcb7b8c2659029395bdf0000000000000000000000000000000000000000000000000000000000000064'

// a function without parameters returns only the selector
tronWeb.utils.abi.encodeFunctionData({ name: 'totalSupply', type: 'function', inputs: [], outputs: [] });
'18160ddd'

// trcToken stays in the selector, value is encoded as uint256
tronWeb.utils.abi.encodeFunctionData(
  { name: 'transfer', type: 'function', inputs: [{ name: 'id', type: 'trcToken' }], outputs: [] },
  [1000100]
);
'e7bf839c00000000000000000000000000000000000000000000000000000000000f42a4'