Removing Liquidity
This guide shows how to remove liquidity from a pool using the SDK and massa-web3. In this example, we will be removing liquidity from a LBPair of USDC/WMAS/20bps
1. Required imports for this guide
import {
ChainId,
EventDecoder,
IRouter,
LB_ROUTER_ADDRESS,
PairV2,
WMAS as _WMAS,
USDC as _USDC,
ILBPair,
Percent,
} from "@dusalabs/sdk";
import {
BUILDNET_CHAIN_ID,
ClientFactory,
DefaultProviderUrls,
EOperationStatus,
ProviderType,
WalletClient,
} from "@massalabs/massa-web3";
2. Declare required constants
const BUILDNET_URL = DefaultProviderUrls.BUILDNET;
const privateKey = process.env.PRIVATE_KEY;
if (!privateKey) throw new Error("Missing PRIVATE_KEY in .env file");
const account = await WalletClient.getAccountFromSecretKey(privateKey);
const address = account.address;
if (!address) throw new Error("Missing address in account");
const client = await ClientFactory.createCustomClient(
[
{ url: BUILDNET_URL, type: ProviderType.PUBLIC },
{ url: BUILDNET_URL, type: ProviderType.PRIVATE },
],
BUILDNET_CHAIN_ID,
true,
account
);
const CHAIN_ID = ChainId.BUILDNET;
Note that in your project, you most likely will not hardcode the private key at any time. You would be using libraries like wallet-provider to connect to a wallet, sign messages, interact with contracts, and get the above constants.
// initialize tokens
const WMAS = _WMAS[CHAIN_ID];
const USDC = _USDC[CHAIN_ID];
const router = LB_ROUTER_ADDRESS[CHAIN_ID];
3. Getting data
LBPair and active bin
const pair = new PairV2(USDC, WMAS);
const binStep = 20;
const lbPair = await pair.fetchLBPair(binStep, client, CHAIN_ID);
const pairAddress = lbPair.LBPair;
const pairContract = new ILBPair(pairAddress, client);
const lbPairData = await pairContract.getReservesAndId();
const tokens = await pairContract.getTokens()
const activeBinId = lbPairData.activeId;
Liquidity positions
const userPositionIds = await pairContract.getUserBinIds(address);
const addressArray = Array.from({ length: userPositionIds.length }, () => address);
const bins = await pairContract.getBins(userPositionIds);
const allBins = await pairContract.balanceOfBatch(addressArray, userPositionIds);
const nonZeroAmounts = allBins.filter((amount) => amount !== 0n);
const totalSupplies = await pairContract.getSupplies(userPositionIds);
4. Grant LBRouter access to your LBTokens
const approved = await pairContract.isApprovedForAll(address, router);
if (!approved) {
const txIdApprove = await pairContract.setApprovalForAll(router, true);
console.log("txIdApprove", txIdApprove);
}
5. Set removeLiquidity parameters
const currentTimeInMs = new Date().getTime();
const deadline = currentTimeInMs + 3_600_000;
// set amount slippage tolerance
const allowedAmountSlippage = 50; // in bips, 0.5% in this case
const removeLiquidityInput = pair.calculateAmountsToRemove(
userPositionIds,
activeBinId,
bins,
totalSupplies,
nonZeroAmounts.map(String),
new Percent(BigInt(allowedAmountSlippage), 10_000n)
);
const params = pair.liquidityCallParameters({
...removeLiquidityInput,
amount0Min: removeLiquidityInput.amountXMin,
amount1Min: removeLiquidityInput.amountYMin,
ids: userPositionIds,
amounts: nonZeroAmounts,
token0: tokens[0],
token1: tokens[1],
binStep,
to: address,
deadline,
});
6. Execute contract call
const txId = await new IRouter(router, client).remove(params);
console.log("txId", txId);
// await transaction confirmation and log output events
const status = await client.smartContracts().awaitRequiredOperationStatus(txId, EOperationStatus.FINAL_SUCCESS);
if (status !== EOperationStatus.FINAL_SUCCESS) throw new Error("Something went wrong");
await client
.smartContracts()
.getFilteredScOutputEvents({
emitter_address: null,
start: null,
end: null,
original_caller_address: null,
is_final: null,
original_operation_id: txId,
})
.then((r) =>
r.forEach(({ data }) => {
if (data.startsWith("WITHDRAWN_FROM_BIN:")) console.log(EventDecoder.decodeLiquidity(data));
else console.log(data);
})
);