用web3js写个对ERC20授权
时间: 2024-02-04 15:03:21 浏览: 37
首先,你需要安装 web3.js 库:
```
npm install web3
```
然后,你可以使用以下代码来编写一个 ERC20 授权的函数:
```javascript
const Web3 = require('web3');
// 初始化 Web3 对象
const web3 = new Web3('http://localhost:8545');
// 定义 ERC20 合约地址和 ABI
const contractAddress = '0x1234567890123456789012345678901234567890';
const contractABI = [
{
"constant": true,
"inputs": [],
"name": "name",
"outputs": [
{
"name": "",
"type": "string"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
{
"constant": true,
"inputs": [],
"name": "symbol",
"outputs": [
{
"name": "",
"type": "string"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
{
"constant": true,
"inputs": [],
"name": "decimals",
"outputs": [
{
"name": "",
"type": "uint8"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
{
"constant": false,
"inputs": [
{
"name": "_spender",
"type": "address"
},
{
"name": "_value",
"type": "uint256"
}
],
"name": "approve",
"outputs": [
{
"name": "",
"type": "bool"
}
],
"payable": false,
"stateMutability": "nonpayable",
"type": "function"
},
{
"constant": true,
"inputs": [
{
"name": "_owner",
"type": "address"
},
{
"name": "_spender",
"type": "address"
}
],
"name": "allowance",
"outputs": [
{
"name": "",
"type": "uint256"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
{
"constant": false,
"inputs": [
{
"name": "_to",
"type": "address"
},
{
"name": "_value",
"type": "uint256"
}
],
"name": "transfer",
"outputs": [
{
"name": "",
"type": "bool"
}
],
"payable": false,
"stateMutability": "nonpayable",
"type": "function"
},
{
"constant": true,
"inputs": [
{
"name": "_owner",
"type": "address"
}
],
"name": "balanceOf",
"outputs": [
{
"name": "balance",
"type": "uint256"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
{
"inputs": [
{
"name": "_initialSupply",
"type": "uint256"
},
{
"name": "_tokenName",
"type": "string"
},
{
"name": "_tokenSymbol",
"type": "string"
}
],
"payable": false,
"stateMutability": "nonpayable",
"type": "constructor"
},
{
"anonymous": false,
"inputs": [
{
"indexed": true,
"name": "_from",
"type": "address"
},
{
"indexed": true,
"name": "_to",
"type": "address"
},
{
"indexed": false,
"name": "_value",
"type": "uint256"
}
],
"name": "Transfer",
"type": "event"
},
{
"anonymous": false,
"inputs": [
{
"indexed": true,
"name": "_owner",
"type": "address"
},
{
"indexed": true,
"name": "_spender",
"type": "address"
},
{
"indexed": false,
"name": "_value",
"type": "uint256"
}
],
"name": "Approval",
"type": "event"
}
];
// 获取 ERC20 合约实例
const contract = new web3.eth.Contract(contractABI, contractAddress);
// 定义授权函数
async function approve(spender, value, from) {
try {
const result = await contract.methods.approve(spender, value).send({ from });
console.log(result);
} catch (error) {
console.error(error);
}
}
// 调用授权函数
approve('0x1234567890123456789012345678901234567890', '1000000000000000000', '0x0123456789012345678901234567890123456789');
```
在上面的代码中,我们首先定义了 ERC20 合约地址和 ABI。然后,我们使用 `web3.eth.Contract` 创建了一个 ERC20 合约实例。最后,我们定义了一个 `approve` 函数,用于授权指定地址可以花费我们的代币。在授权函数中,我们使用 `contract.methods.approve` 方法来调用 ERC20 合约中的 `approve` 函数,并使用 `send` 方法发送交易。最后,我们调用 `approve` 函数,并传入要授权的地址、要授权的数量和发送交易的地址参数。