@tronwidgets/transaction
v1.0.0
Published
## Introduction
Downloads
14
Maintainers
troncoreReadme
@tronwidgets/transaction
Introduction
The lib can help DApp developers trigger contract transactions, query contract methods, etc. With transaction, DApp developers will be able to:
- build transaction, sign and broadcast
- use the call or view method to query the specific parameters of the contract
- deploy contract
- send trx or other token
Installation
npm i @tronwidgets/transaction
API List
Documentation
Code Example
Import it at the top of your code.
import { ContractInteract } from "@tronwidgets/transaction";Contract function may require a Tron wallet address as target recipient.
const ACCOUNT = "TBHHa5Z6WQ1cRcgUhdvqdW4f728f2fiJmF";Token contract (BTT @ nile testnet).
const CONTRACT = "TNuoKL1ni8aoshfFL1ASca1Gou9RXwAzfn";Token contract (BTT(TRC20) @ nile testnet).
const CONTRACT_2 = "TBagxx57zx73VJJ61o12VfxzQ2EG3KHYJp";The ABI code example is located at the end of the document.
All functions are asynchronous and the await keyword is permitted within it. The return type is Promise object.
Check "~/defi-demo/src/routes/contract.js" for real world implementation.
Check "~/packages/transaction/src/index.ts" or "~/packages/transaction/dist/index.d.ts" for code source.
Time to BUILD
trigger
parameters:
(address: any, functionSelector: any, options, parameters, { tronweb }?: {
tronweb?: {} | undefined;
})example:
const response = await ContractInteract.trigger(
"TGjgvdTWWrybVLaVeFqSyVqJQWjxqRYbaK", // Decentralized USD (USDD)
"name()",
[]
)
// convert response.constant_result from Hex to ASCII to retrieve string valueresponse:
{
"result": {
"result": true
},
"energy_used": 903,
"constant_result": [
"00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000011446563656e7472616c697a656420555344000000000000000000000000000000"
],
"transaction": {
"ret": [
{}
],
"visible": false,
"txID": "034888a1b4492b71189d72dfacacbb75b1a59b339e596d1c0fab679cb4ca167a",
"raw_data": {
"contract": [
{
"parameter": {
"value": {
"data": "06fdde03",
"owner_address": "41c4ae90260992e400b449011a49374e6cdc95f67a",
"contract_address": "414a3a5dd265bd974b4de0bbe33faa7efb8b7b87e8"
},
"type_url": "type.googleapis.com/protocol.TriggerSmartContract"
},
"type": "TriggerSmartContract"
}
],
"ref_block_bytes": "5f50",
"ref_block_hash": "6d01101e64239ef7",
"expiration": 1652860608000,
"fee_limit": 150000000,
"timestamp": 1652860548453
},
"raw_data_hex": "0a025f5022086d01101e64239ef74080bcadb18d305a6d081f12690a31747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e54726967676572536d617274436f6e747261637412340a1541c4ae90260992e400b449011a49374e6cdc95f67a1215414a3a5dd265bd974b4de0bbe33faa7efb8b7b87e8220406fdde0370e5eaa9b18d30900180a3c347"
}
}sign
parameters:
(transaction: any, { tronweb }?: { tronweb?: {} | undefined; })example:
const { transaction, result } = await window.tronWeb.transactionBuilder.triggerSmartContract(
CONTRACT,
"transfer(address,uint256)",
{
feeLimit: 1_000_000,
callValue: 0
},
[{
type: "address",
value: ACCOUNT
}, {
type: "uint256",
value: 1000000
}]
);
if (!result.result) {
console.error("error:", result);
return;
}
const response = await window.tronWeb.trx.sign(transaction);response:
{
"visible": false,
"txID": "093e9f4b3ba31c6429fa0b1b22f10281886e6bbe5ecb97bb25c721497c291231",
"raw_data": {
"contract": [
{
"parameter": {
"value": {
"data": "a9059cbb0000000000000000000000000e636d680b300214cf10e3343d0eef14f642c8a400000000000000000000000000000000000000000000000000000000000f4240",
"owner_address": "41c4ae90260992e400b449011a49374e6cdc95f67a",
"contract_address": "418df49db5dbf07e498492d2dafcf7b305cdc72471"
},
"type_url": "type.googleapis.com/protocol.TriggerSmartContract"
},
"type": "TriggerSmartContract"
}
],
"ref_block_bytes": "6101",
"ref_block_hash": "1f3cbafca3705dd1",
"expiration": 1652861919000,
"fee_limit": 1000000,
"timestamp": 1652861859565
},
"raw_data_hex": "0a02610122081f3cbafca3705dd14098befdb18d305aae01081f12a9010a31747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e54726967676572536d617274436f6e747261637412740a1541c4ae90260992e400b449011a49374e6cdc95f67a1215418df49db5dbf07e498492d2dafcf7b305cdc724712244a9059cbb0000000000000000000000000e636d680b300214cf10e3343d0eef14f642c8a400000000000000000000000000000000000000000000000000000000000f424070ededf9b18d309001c0843d",
"signature": [
"5401945088ec48ee611d871fe251756678c487b4b314a8c45306337084ca3ee52975152d64aafcc5438e737f93cd1f03b00df5b208ec91a5371c28d79da352fa00"
]
}broadcast
parameters:
(signedTransaction: any, { tronweb }?: { tronweb?: {} | undefined; })example:
const address = "TDqjTkZ63yHB19w2n7vPm2qAkLHwn9fKKk";
const functionSelector = "approve(address,uint256)";
const exchangeAddress = "TH1SvdkzHbeN7gYPKhtoDPtFe3V2nj9yVv";
const MAX_UINT256 = "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff";
const feeLimitCommon = 400000000;
const feeLimitMin = 100000000;
const parameters = [
{ type: "address", value: exchangeAddress },
{ type: "uint256", value: MAX_UINT256 }
];
const transaction = await ContractInteract.trigger(
address,
functionSelector,
Object.assign({ feeLimit: feeLimitCommon },{ feeLimit: feeLimitMin }),
parameters
);
if (!transaction.result || !transaction.result.result) {
throw new Error("Unknown trigger error: " + JSON.stringify(transaction.transaction));
}
const signedTransaction = await ContractInteract.sign(transaction.transaction);
const response = await ContractInteract.broadcast(signedTransaction);transaction:
{
"result": {
"result": true
},
"transaction": {
"visible": false,
"txID": "60a8c18dbe622bbdc6c67cd289f012589bd1b71ebbb0826d2834c40b54f12273",
"raw_data": {
"contract": [
{
"parameter": {
"value": {
"data": "095ea7b3",
"owner_address": "41c4ae90260992e400b449011a49374e6cdc95f67a",
"contract_address": "412a769a33b6ed01a074e4a45bffa0778a27949bec"
},
"type_url": "type.googleapis.com/protocol.TriggerSmartContract"
},
"type": "TriggerSmartContract"
}
],
"ref_block_bytes": "622e",
"ref_block_hash": "1f79b52388ace764",
"expiration": 1652862834000,
"fee_limit": 150000000,
"timestamp": 1652862775340
},
"raw_data_hex": "0a02622e22081f79b52388ace76440d0aab5b28d305a6d081f12690a31747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e54726967676572536d617274436f6e747261637412340a1541c4ae90260992e400b449011a49374e6cdc95f67a1215412a769a33b6ed01a074e4a45bffa0778a27949bec2204095ea7b370ace0b1b28d30900180a3c347"
}
}signedTransaction:
{
"visible": false,
"txID": "f80c9c44d2641da98c128b729d1251da8e21c0bc7a55b0def102f5225d21cc63",
"raw_data": {
"contract": [
{
"parameter": {
"value": {
"data": "095ea7b3",
"owner_address": "41c4ae90260992e400b449011a49374e6cdc95f67a",
"contract_address": "412a769a33b6ed01a074e4a45bffa0778a27949bec"
},
"type_url": "type.googleapis.com/protocol.TriggerSmartContract"
},
"type": "TriggerSmartContract"
}
],
"ref_block_bytes": "622e",
"ref_block_hash": "1f79b52388ace764",
"expiration": 1652862834000,
"fee_limit": 150000000,
"timestamp": 1652862775617
},
"raw_data_hex": "0a02622e22081f79b52388ace76440d0aab5b28d305a6d081f12690a31747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e54726967676572536d617274436f6e747261637412340a1541c4ae90260992e400b449011a49374e6cdc95f67a1215412a769a33b6ed01a074e4a45bffa0778a27949bec2204095ea7b370c1e2b1b28d30900180a3c347",
"signature": [
"8c5f61d3f68d5f1d52170ecb9c941df9b7a2c4e0be89e1d3cb3e9d6c5ff2edcbf728a5809c3b736f15437aa7b79cd669825f2f58f930ce723bfaa1ef8cebfdb400"
]
}response:
{
"result": true,
"txid": "f80c9c44d2641da98c128b729d1251da8e21c0bc7a55b0def102f5225d21cc63",
"transaction": {
"visible": false,
"txID": "f80c9c44d2641da98c128b729d1251da8e21c0bc7a55b0def102f5225d21cc63",
"raw_data": {
"contract": [
{
"parameter": {
"value": {
"data": "095ea7b3",
"owner_address": "41c4ae90260992e400b449011a49374e6cdc95f67a",
"contract_address": "412a769a33b6ed01a074e4a45bffa0778a27949bec"
},
"type_url": "type.googleapis.com/protocol.TriggerSmartContract"
},
"type": "TriggerSmartContract"
}
],
"ref_block_bytes": "622e",
"ref_block_hash": "1f79b52388ace764",
"expiration": 1652862834000,
"fee_limit": 150000000,
"timestamp": 1652862775617
},
"raw_data_hex": "0a02622e22081f79b52388ace76440d0aab5b28d305a6d081f12690a31747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e54726967676572536d617274436f6e747261637412340a1541c4ae90260992e400b449011a49374e6cdc95f67a1215412a769a33b6ed01a074e4a45bffa0778a27949bec2204095ea7b370c1e2b1b28d30900180a3c347",
"signature": [
"8c5f61d3f68d5f1d52170ecb9c941df9b7a2c4e0be89e1d3cb3e9d6c5ff2edcbf728a5809c3b736f15437aa7b79cd669825f2f58f930ce723bfaa1ef8cebfdb400"
]
}
}send
parameters:
(address: any, functionSelector: any, options, parameters, { tronweb }?: {
tronweb?: {} | undefined;
})example:
const response = await ContractInteract.send(
ACCOUNT,
"postMessage(string)",
[{ type: "string", value: "Hello" }]
);response:
{
"result": true,
"txid": "75901bee90e7134590c47df2af885e281f251270572328ee258b26a2271dd4f4",
"transaction": {
"visible": false,
"txID": "75901bee90e7134590c47df2af885e281f251270572328ee258b26a2271dd4f4",
"raw_data": {
"contract": [
{
"parameter": {
"value": {
"data": "6630f88f0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000548656c6c6f000000000000000000000000000000000000000000000000000000",
"owner_address": "41c4ae90260992e400b449011a49374e6cdc95f67a",
"contract_address": "41766510af1f0d793718f22de068600089da9af9d0"
},
"type_url": "type.googleapis.com/protocol.TriggerSmartContract"
},
"type": "TriggerSmartContract"
}
],
"ref_block_bytes": "4dd5",
"ref_block_hash": "bac6a76f7be8c97e",
"expiration": 1652847045000,
"fee_limit": 150000000,
"timestamp": 1652846986508
},
"raw_data_hex": "0a024dd52208bac6a76f7be8c97e4088d3f1aa8d305acf01081f12ca010a31747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e54726967676572536d617274436f6e74726163741294010a1541c4ae90260992e400b449011a49374e6cdc95f67a121541766510af1f0d793718f22de068600089da9af9d022646630f88f0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000548656c6c6f000000000000000000000000000000000000000000000000000000708c8aeeaa8d30900180a3c347",
"signature": [
"37185e7e01b1ff00ae1d661af9c51230ff10cfbab33a3ace970116a47783491bc06640705ab3a7311721e9be1f3ecc5d659d27854ef1283ebb8ab2585d382b9000"
]
}
}call
parameters:
(address: string, _functionSelector: any, { tronweb, abi }?: {
tronweb?: {} | undefined;
abi?: never[] | undefined;
})example:
const response = await call(
ACCOUNT,
"getMessage()",
{ abi: funcABIV2.abi }
);response:
{
"result": "Hello"
}view
parameters:
(address: string, _functionSelector: any, parameters = []{ tronweb } ?: {
tronweb?: {} | undefined;
})example:
const response = await view(
CONTRACT_2,
"totalSupply()",
[]
);response:
{
"result": {
"result": true
},
"energy_used": 924,
"constant_result": [
"0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000548656c6c6f000000000000000000000000000000000000000000000000000000"
],
"transaction": {
"ret": [
{}
],
"visible": false,
"txID": "85b4730e278ca5f253e3e3ebf5e9f8526c2c89e2566c23e14fb8187388295994",
"raw_data": {
"contract": [
{
"parameter": {
"value": {
"data": "ce6d41de",
"owner_address": "4165fa68800fff5a10346d1a3aa1fb2ce92f2e2971",
"contract_address": "41766510af1f0d793718f22de068600089da9af9d0"
},
"type_url": "type.googleapis.com/protocol.TriggerSmartContract"
},
"type": "TriggerSmartContract"
}
],
"ref_block_bytes": "7e84",
"ref_block_hash": "c118a5e68d514097",
"expiration": 1662021381000,
"timestamp": 1662021324119
},
"raw_data_hex": "0a027e842208c118a5e68d5140974088d7c6c1af305a6d081f12690a31747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e54726967676572536d617274436f6e747261637412340a154165fa68800fff5a10346d1a3aa1fb2ce92f2e2971121541766510af1f0d793718f22de068600089da9af9d02204ce6d41de70d79ac3c1af30"
}
}deploy
parameters:
(options: any, address: string, { callbacks, tronweb }?: {
callbacks?: (() => void) | undefined;
tronweb?: {} | undefined;
})example:
const deployOptions = {
abi: funcABIV2.abi,
bytecode: funcABIV2.bytecode,
funcABIV2: funcABIV2.abi[0],
parametersV2: [1]
}
const response = await ContractInteract.deploy(deployOptions);response:
{
"result": true,
"txid": "54e91f79a5b88e76eb100dcd288bcba1d726912024dd783f12a767123b8fe9dd",
"transaction": {
"visible": false,
"txID": "54e91f79a5b88e76eb100dcd288bcba1d726912024dd783f12a767123b8fe9dd",
"contract_address": "4194abf50b4cae22905c1d383899d36019b372db35",
"raw_data": {
"contract": [
{
"parameter": {
"value": {
"owner_address": "41c4ae90260992e400b449011a49374e6cdc95f67a",
"new_contract": {
"bytecode": "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",
"consume_user_resource_percent": 100,
"origin_address": "41c4ae90260992e400b449011a49374e6cdc95f67a",
"abi": {
"entrys": [
{
"outputs": [
{
"type": "string"
}
],
"inputs": [
{
"name": "value",
"type": "string"
}
],
"name": "postMessage",
"stateMutability": "Nonpayable",
"type": "Function"
},
{
"outputs": [
{
"type": "string"
}
],
"constant": true,
"name": "getMessage",
"stateMutability": "View",
"type": "Function"
}
]
},
"origin_energy_limit": 10000000
}
},
"type_url": "type.googleapis.com/protocol.CreateSmartContract"
},
"type": "CreateSmartContract"
}
],
"ref_block_bytes": "4f29",
"ref_block_hash": "cbdc889b7afcb668",
"expiration": 1652848077000,
"fee_limit": 150000000,
"timestamp": 1652848019189
},
"raw_data_hex": "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",
"signature": [
"be094b056dd6ef725698aa5e89ca9c7e32d2d43ec04d27a290c8d3f0581f754e0cb3c5536c8cef7670ee67e487658cf3d0f2aee3673a9726fd42340c1089227601"
]
}
}sendTrx
parameters:
(toAddress: string, amount: string | number, fromAddress: string, options: any, { callbacks, tronweb }?: {
callbacks?: (() => void) | undefined;
tronweb?: {} | undefined;
})example:
const response = await ContractInteract.sendTrx(
"TBHHa5Z6WQ1cRcgUhdvqdW4f728f2fiJmF",
1000000
);response:
{
"result": true,
"txid": "1fd5f9483ecdc6a7ae0897d24be14d3de6d43afbe1e4c2ca675fdaa5bb551bf8",
"transaction": {
"visible": false,
"txID": "1fd5f9483ecdc6a7ae0897d24be14d3de6d43afbe1e4c2ca675fdaa5bb551bf8",
"raw_data": {
"contract": [
{
"parameter": {
"value": {
"amount": 1000000,
"owner_address": "41c4ae90260992e400b449011a49374e6cdc95f67a",
"to_address": "410e636d680b300214cf10e3343d0eef14f642c8a4"
},
"type_url": "type.googleapis.com/protocol.TransferContract"
},
"type": "TransferContract"
}
],
"ref_block_bytes": "5098",
"ref_block_hash": "ae68369446756cd2",
"expiration": 1652849190000,
"timestamp": 1652849132334
},
"raw_data_hex": "0a0250982208ae68369446756cd240f0c8f4ab8d305a67080112630a2d747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e5472616e73666572436f6e747261637412320a1541c4ae90260992e400b449011a49374e6cdc95f67a1215410e636d680b300214cf10e3343d0eef14f642c8a418c0843d70ae86f1ab8d30",
"signature": [
"1a108d49e226fe184d8dbb7b03f3453ebd07c9ffbcb21a400229668e01c9287190cb7027a884244bc7a790d911f48e98c58ff7eee338554fb618260db5f3f5fe00"
]
}
}sendToken
parameters:
(address: string, amount: string | number, tokenID: string | number, privateKey: string, { callbacks, tronweb }?: {
callbacks?: (() => void) | undefined;
tronweb?: {} | undefined;
})example:
const response = await ContractInteract.sendToken(
ACCOUNT,
10000,
"1000617"
);response:
{
"result": true,
"txid": "23d404c13f9850ae265cb9cabe83fd34802de60d08830c13b36ec1879fc0bd72",
"transaction": {
"visible": false,
"txID": "23d404c13f9850ae265cb9cabe83fd34802de60d08830c13b36ec1879fc0bd72",
"raw_data": {
"contract": [
{
"parameter": {
"value": {
"amount": 10000,
"asset_name": "31303030363137",
"owner_address": "41c4ae90260992e400b449011a49374e6cdc95f67a",
"to_address": "410e636d680b300214cf10e3343d0eef14f642c8a4"
},
"type_url": "type.googleapis.com/protocol.TransferAssetContract"
},
"type": "TransferAssetContract"
}
],
"ref_block_bytes": "58fd",
"ref_block_hash": "386870048618a656",
"expiration": 1652855703000,
"timestamp": 1652855644792
},
"raw_data_hex": "0a0258fd2208386870048618a65640d88b82af8d305a74080212700a32747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e5472616e736665724173736574436f6e7472616374123a0a0731303030363137121541c4ae90260992e400b449011a49374e6cdc95f67a1a15410e636d680b300214cf10e3343d0eef14f642c8a420904e70f8c4feae8d30",
"signature": [
"d0ea580ccff32bd595e5df2ac82cebdae125ad9f156094b57320e6cfe301d31b9ac53d3179cfb47a27aaa7c6a5037de9334e7da0a58256e6da19e5a7dd42138b00"
]
}
}Licence
TronWeb is distributed under a MIT licence.