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DELTA.md

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Velora Delta is an intent-based protocol that enables a Velora user to make gasless swaps where multiple agents compete to execute the trade at the best price possible. This way the user doesn't need to make a transaction themselves but only to sign a Delta Order. The easiest way to make use of the Delta Order is to use the SDK following these steps:

1. Construct an SDK object

const account = userAddress;
const deltaSDK = constructSimpleSDK(
  {chainId: 1, axios},
  {
    ethersProviderOrSigner: provider, // JsonRpcProvider
    EthersContract: ethers.Contract,
    account,
  });
  // for usage with different web3 provider libraries refer to the main [README](./README.md)

2. Request prices for a Token pair

const DAI_TOKEN = '0x6b175474e89094c44da98b954eedeac495271d0f';
const USDC_TOKEN = '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48';
const amount = '1000000000000'; // in wei

const deltaPrice = await deltaSDK.getDeltaPrice({
  srcToken: DAI_TOKEN,
  destToken: USDC_TOKEN,
  amount,
  userAddress: account,
  srcDecimals: 18,
  destDecimals: 6,
  // partner: "..." // if available
});

3. Approve srcToken for DeltaContract

const tx = await deltaSDK.approveTokenForDelta(amount, DAI_TOKEN);
await tx.wait();

Alternatively sign Permit (DAI or Permit1) or Permit2 TransferFrom with DeltaContract as the verifyingContract

const DeltaContract = await deltaSDK.getDeltaContract();

// values depend on the Permit type and the srcToken
const signature = await signer._signTypedData(domain, types, message);

See more on accepted Permit variants in Velora documentation

4. Sign and submit a Delta Order

// calculate acceptable destAmount
const slippagePercent = 0.5;
  const destAmountAfterSlippage = (
    +deltaPrice.destAmount *
    (1 - slippagePercent / 100)
  ).toString(10);

const deltaAuction = await deltaSDK.submitDeltaOrder({
  deltaPrice,
  owner: account,
  // beneficiary: anotherAccount, // if need to send destToken to another account
  // permit: "0x1234...", // if signed a Permit1 or Permit2 TransferFrom for DeltaContract
  srcToken: DAI_TOKEN,
  destToken: USDC_TOKEN,
  srcAmount: amount,
  destAmount: destAmountAfterSlippage, // minimum acceptable destAmount
});

5. Wait for Delta Order execution

// poll if necessary
function isExecutedDeltaAuction(
  auction: Omit<DeltaAuction, 'signature'>,
  waitForCrosschain = true // only consider executed when destChain work is done
) {
  if (auction.status !== 'EXECUTED') return false;

  // crosschain Order is executed on destChain if bridgeStatus is filled
  if (waitForCrosschain && auction.order.bridge.destinationChainId !== 0) {
    return auction.bridgeStatus === 'filled';
  }

  return true;
}

function fetchOrderPeriodically(auctionId: string) {
  const intervalId = setInterval(async () => {
    const auction = await simpleSDK.delta.getDeltaOrderById(auctionId);
    console.log('checks: ', auction); // Handle or log the fetched auction as needed

    if (isExecutedDeltaAuction(auction)) {
      clearInterval(intervalId); // Stop interval if completed
      console.log('Order completed');
    }
  }, 3000);
  console.log('Order Pending');
  // Return intervalId to enable clearing the interval if needed externally
  return intervalId;
}

function startStatusCheck(auctionId: string) {
  const intervalId = fetchOrderPeriodically(auctionId);
  setTimeout(() => clearInterval(intervalId), 60000 * 5); // Stop after 5 minutes
}

startStatusCheck(deltaAuction.id);

A more detailed example of Delta Order usage can be found in examples/delta

Crosschain Delta Orders

In case you want to perform a crosschain swap, the process is a little more involved.

1. Construct an SDK object

const SRC_CHAIN_ID = 1 // Ethereum
const DEST_CHAIN_ID = 10; // Optimism

const account = userAddress;
const deltaSDK = constructSimpleSDK(
  {chainId: SRC_CHAIN_ID, axios},
  {
    ethersProviderOrSigner: provider, // JsonRpcProvider
    EthersContract: ethers.Contract,
    account,
  });
  // for usage with different web3 provider libraries refer to the main [README](./README.md)

2. Check which tokens are available on the destination chain.

A limited list of tokens are available in Across, the service facilitating crosschain bridging

const bridgeInfo = await deltaSDK.getBridgeInfo();

const tokensAvailableForBridging = bridgeInfo[SRC_CHAIN_ID]?.[DEST_CHAIN_ID]

3. Request prices for a Token pair

const DAI_TOKEN = '0x6b175474e89094c44da98b954eedeac495271d0f';

const USDC_TOKEN_ON_DEST_CHAIN = '0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85'; // available for bridging on Optimism
const amount = '1000000000000'; // in wei

const deltaPrice = await deltaSDK.getDeltaPrice({
  srcToken: DAI_TOKEN,
  destToken: USDC_TOKEN_ON_DEST_CHAIN,
  destChainId: DEST_CHAIN_ID, // required to get deltaPrice for a Crosschain Order
  amount,
  userAddress: account,
  srcDecimals: 18,
  destDecimals: 6,
  // partner: "..." // if available
});

4. Approve srcToken for DeltaContract

const tx = await deltaSDK.approveTokenForDelta(amount, DAI_TOKEN);
await tx.wait();

Alternatively sign Permit (DAI or Permit1) or Permit2 TransferFrom with DeltaContract as the verifyingContract

const DeltaContract = await deltaSDK.getDeltaContract();

// values depend on the Permit type and the srcToken
const signature = await signer._signTypedData(domain, types, message);

See more on accepted Permit variants in Velora documentation

5. Sign and submit a Delta Order

// calculate acceptable destAmount
const slippagePercent = 0.5;
const destAmountAfterSlippage = (
  +deltaPrice.destAmount *
  (1 - slippagePercent / 100)
).toString(10);

const deltaAuction = await deltaSDK.submitDeltaOrder({
  deltaPrice,
  owner: account,
  // permit: "0x1234...", // if signed a Permit1 or Permit2 TransferFrom for DeltaContract
  srcToken: DAI_TOKEN,
  destToken: USDC_TOKEN_ON_DEST_CHAIN,
  srcAmount: amount,
  destAmount: destAmountAfterSlippage, // minimum acceptable destAmount
  destChainId: DEST_CHAIN_ID, // required to construct a Crosschain Order
  beneficiary: anotherAccount, // if need to send destToken to another account on destChain
  beneficiaryType: 'EOA', // whether the beneficiary on destChain is a smart contract
  // bridge, // user-constructed Bridge object for Crosschain Orders
});

To construct a Crosschain Delta Order it is required to either:

  • provide both beneficiary address and beneficiaryType value, so that the Order.bridge can be constructed automatically by the SDK.
  • construct Bridge object. Refer to documentation for how to do that.

This is necessary because Across, the service facilitating crosschain bridging, has special logic when it comes to transferring ETH and WETH.

5. Wait for Delta Order execution

// poll if necessary
function isExecutedDeltaAuction(
  auction: Omit<DeltaAuction, 'signature'>,
  waitForCrosschain = true // only consider executed when destChain work is done
) {
  if (auction.status !== 'EXECUTED') return false;

  // crosschain Order is executed on destChain if bridgeStatus is filled
  if (waitForCrosschain && auction.order.bridge.destinationChainId !== 0) {
    return auction.bridgeStatus === 'filled';
  }

  return true;
}

function fetchOrderPeriodically(auctionId: string) {
  const intervalId = setInterval(async () => {
    const auction = await simpleSDK.delta.getDeltaOrderById(auctionId);
    console.log('checks: ', auction); // Handle or log the fetched auction as needed

    if (isExecutedDeltaAuction(auction)) {
      clearInterval(intervalId); // Stop interval if completed
      console.log('Order completed');
    }
  }, 3000);
  console.log('Order Pending');
  // Return intervalId to enable clearing the interval if needed externally
  return intervalId;
}

function startStatusCheck(auctionId: string) {
  const intervalId = fetchOrderPeriodically(auctionId);
  setTimeout(() => clearInterval(intervalId), 60000 * 5); // Stop after 5 minutes
}

startStatusCheck(deltaAuction.id);