triggerConstantContract

Trigger the read-only function of the contract ( they are the contract function which decorated by the pure and view modifiers), the query result is a non-solidified state.

Usage

const transactionWrapper = tronWeb.transactionBuilder.triggerConstantContract(contractAddress, functionSelector, options, parameter, ownerAddress);

Parameters

Argument	Description	Type
contractAddress	The smart contract address.	String
functionSelector	Function to call, must not leave a blank space	String
options	Options for trigger smart contract	TriggerSmartContractOptions
parameter	The parameter passed to function	Array<{ type: string; value: unknown }>
ownerAddress	Address in hex which calls the function	String

Returns

A wrapper which contains unsigned transaction object.

interface TransactionWrapper {
    result: {
        result: boolean;
    };
    /**
     * The transaction object created by calling contract function.
     */
    transaction: Transaction;
    /**
     * Energy used by triggering contract.
     */
    energy_used?: number;
    /**
     * The total penalty energy in the transaction
     */
    energy_penalty?: number;
    /**
     * Result of calling contract function which is decorated by `view` or `pure`.
     */
    constant_result?: string[];
}

Example

const parameter = [{ type: 'address', value: 'TV3nb5HYFe2xBEmyb3ETe93UGkjAhWyzrs' }, { type: 'uint256', value: 100 }];
const transactionWrapper = await tronWeb.transactionBuilder.triggerConstantContract("419e62be7f4f103c36507cb2a753418791b1cdc182", "transfer(address,uint256)", {}, parameter, "417946F66D0FC67924DA0AC9936183AB3B07C81126");
console.log(transactionWrapper);
> {
    "result": {
        "result": true
    },
    "energy_used": 29631,
    "constant_result": [
        "0000000000000000000000000000000000000000000000000000000000000000"
    ],
    "logs": [
        {
            "address": "9e62be7f4f103c36507cb2a753418791b1cdc182",
            "data": "0000000000000000000000000000000000000000000000000000000000000064",
            "topics": [
                "ddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
                "0000000000000000000000007946f66d0fc67924da0ac9936183ab3b07c81126",
                "000000000000000000000000d148171f1ceeeb40d668c47d70e7e94e67977559"
            ]
        }
    ],
    "transaction": {
        "ret": [
            {}
        ],
        "visible": false,
        "txID": "5c280444c82f3050e4b0c672ab98bae264830d80b09db6c861b31699f6bcaaa8",
        "raw_data": {
            "contract": [
                {
                    "parameter": {
                        "value": {
                            "data": "a9059cbb000000000000000000000000d148171f1ceeeb40d668c47d70e7e94e679775590000000000000000000000000000000000000000000000000000000000000064",
                            "owner_address": "417946f66d0fc67924da0ac9936183ab3b07c81126",
                            "contract_address": "419e62be7f4f103c36507cb2a753418791b1cdc182"
                        },
                        "type_url": "type.googleapis.com/protocol.TriggerSmartContract"
                    },
                    "type": "TriggerSmartContract"
                }
            ],
            "ref_block_bytes": "3d8f",
            "ref_block_hash": "316b196f79afe0dc",
            "expiration": 1649655780000,
            "timestamp": 1649655730243
        },
        "raw_data_hex": "0a023d8f2208316b196f79afe0dc40a0a596b981305aae01081f12a9010a31747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e54726967676572536d617274436f6e747261637412740a15417946f66d0fc67924da0ac9936183ab3b07c811261215419e62be7f4f103c36507cb2a753418791b1cdc1822244a9059cbb000000000000000000000000d148171f1ceeeb40d668c47d70e7e94e67977559000000000000000000000000000000000000000000000000000000000000006470c3a093b98130"
    }
}

Note: After GreatVoyage-v4.3.0(Bacon), user can invoke the read-only method as well as the non-read-only method of a contract via wallet/triggerconstantcontract API, and there is a new field energy_limit in the return value, it means the actual energy consumption of this contract invoking. This API can be used to forecast energy usage.