four-flap-meme-sdk/dist/flap/permit.js

SDK for Flap bonding curve and four.meme TokenManager

import { Wallet, AbiCoder, Contract, JsonRpcProvider } from 'ethers';
import { FLAP_PORTAL_ADDRESSES } from './constants.js';
import { CHAIN } from '../utils/constants.js';
/**
 * 构建 Permit Piggyback 数据
 * 自动签名并使用正确的 Portal 代理地址
 *
 * @param chain 链名称
 * @param privateKey 用户私钥
 * @param tokenAddress ERC20 代币地址（需要支持 EIP-2612 Permit）
 * @param value 授权金额
 * @param deadline 截止时间戳
 * @param nonce Permit nonce（通常从代币合约的 nonces(owner) 获取）
 * @returns Permit Piggyback 编码数据（Hex string）
 */
export async function buildPermitPiggybackAuto(chain, privateKey, tokenAddress, value, deadline, nonce, opts) {
    const spender = FLAP_PORTAL_ADDRESSES[chain];
    if (!spender) {
        throw new Error(`Flap Portal not deployed on ${chain}`);
    }
    // 创建钱包
    const wallet = new Wallet(privateKey);
    const owner = wallet.address;
    // 获取 chainId
    const chainId = CHAIN[chain].chainId;
    // 读取代币 name（优先 override，其次链上查询，不可用时回退为空字符串）
    let tokenName = opts?.tokenNameOverride ?? '';
    if (!tokenName && opts?.rpcUrl) {
        try {
            const erc20 = new Contract(tokenAddress, ['function name() view returns (string)'], new JsonRpcProvider(opts.rpcUrl));
            tokenName = await erc20.name();
        }
        catch { }
    }
    // 构建 EIP-2612 Permit 消息（name 可能为空字符串，符合部分实现）
    const domain = {
        name: tokenName,
        version: '1',
        chainId,
        verifyingContract: tokenAddress,
    };
    const types = {
        Permit: [
            { name: 'owner', type: 'address' },
            { name: 'spender', type: 'address' },
            { name: 'value', type: 'uint256' },
            { name: 'nonce', type: 'uint256' },
            { name: 'deadline', type: 'uint256' },
        ],
    };
    const message = {
        owner,
        spender,
        value: value.toString(),
        nonce: nonce.toString(),
        deadline: deadline.toString(),
    };
    // 签名
    const signature = await wallet.signTypedData(domain, types, message);
    // 解析签名为 v, r, s
    const r = `0x${signature.slice(2, 66)}`;
    const s = `0x${signature.slice(66, 130)}`;
    const v = parseInt(signature.slice(130, 132), 16);
    // 使用 ethers AbiCoder 编码 Permit Piggyback 数据
    const abiCoder = AbiCoder.defaultAbiCoder();
    return abiCoder.encode(['address', 'address', 'uint256', 'uint256', 'uint8', 'bytes32', 'bytes32'], [owner, spender, value, deadline, v, r, s]);
}