join.ts

import dotenv from 'dotenv';
import { JsonRpcProvider } from '@ethersproject/providers';
import {
  BalancerError,
  BalancerErrorCode,
  BalancerSDK,
  Network,
  PoolWithMethods,
} from '../src/index';
import { forkSetup, getBalances } from '../src/test/lib/utils';
import { ADDRESSES } from '../src/test/lib/constants';

dotenv.config();

const { ALCHEMY_URL: jsonRpcUrl } = process.env;

/*
Example showing how to use Pools module to join pools.
*/
async function join() {
  const network = Network.MAINNET;
  const rpcUrl = 'http://127.0.0.1:8545';
  const provider = new JsonRpcProvider(rpcUrl, network);
  const signer = provider.getSigner();
  const signerAddress = await signer.getAddress();

  // 50/50 WBTC/WETH Pool
  const poolId = ADDRESSES[network].WBTCWETH?.id as string;
  // Tokens that will be provided to pool by joiner
  const tokensIn = [
    ADDRESSES[network].WBTC?.address,
    ADDRESSES[network].WETH?.address,
  ] as string[];
  // Slots used to set the account balance for each token through hardhat_setStorageAt
  // Info fetched using npm package slot20
  const slots = [
    ADDRESSES[network].WBTC?.slot,
    ADDRESSES[network].WETH?.slot,
  ] as number[];

  const amountsIn = ['10000000', '1000000000000000000'];
  const slippage = '100'; // 100 bps = 1%

  const sdkConfig = {
    network,
    rpcUrl,
  };
  const balancer = new BalancerSDK(sdkConfig);

  // Sets up local fork granting signer initial balances and token approvals
  await forkSetup(signer, tokensIn, slots, amountsIn, jsonRpcUrl as string);

  // Use SDK to find pool info
  const pool: PoolWithMethods | undefined = await balancer.pools.find(poolId);
  if (!pool) throw new BalancerError(BalancerErrorCode.POOL_DOESNT_EXIST);

  // Checking balances to confirm success
  const tokenBalancesBefore = (
    await getBalances([pool.address, ...pool.tokensList], signer, signerAddress)
  ).map((b) => b.toString());

  // Use SDK to create join
  const { to, data, minBPTOut } = pool.buildJoin(
    signerAddress,
    tokensIn,
    amountsIn,
    slippage
  );

  // Calculate price impact
  const priceImpact = await pool.calcPriceImpact(amountsIn, minBPTOut, true);

  // Submit join tx
  const transactionResponse = await signer.sendTransaction({
    to,
    data,
    // gasPrice: '6000000000', // gas inputs are optional
    // gasLimit: '2000000', // gas inputs are optional
  });

  await transactionResponse.wait();
  const tokenBalancesAfter = (
    await getBalances([pool.address, ...pool.tokensList], signer, signerAddress)
  ).map((b) => b.toString());

  console.log('Balances before exit:        ', tokenBalancesBefore);
  console.log('Balances after exit:         ', tokenBalancesAfter);
  console.log('Min BPT expected after exit: ', [minBPTOut.toString()]);
}

// yarn examples:run ./examples/join.ts
join();