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Propose Price

Once a request has been made, Proposers respond by referencing off-chain price feeds and submitting a value to the Optimistic Oracle contract. The customAncillaryData for the contract we deployed is:

q: title: NBA: Who will win Heat vs. Hawks, scheduled for April 19, 7:30 PM ET?, p1: 0, p2: 1, p3: 0.5. Where p2 corresponds to Heat, p1 to a Hawks, p3 to unknown

After referencing the score for the game, we determine the Heat won. To propose a value, we include the proposedPrice of 1 (Heat => p2:1) with the priceIdentifier, timestamp, and ancillaryData parameters from the request.

Note: If using the example below, make sure to input your LSP contract address for the lspAddress constant below.

// Helper modulesconst { getAddress } = require("@uma/contracts-node");const { getContract, web3 } = require("hardhat");const { toBN, toWei } = web3.utils;
// Constants to updateconst chainId = 42;const lspAddress = "YOUR_LSP_CONTRACT_ADDRESS";const proposedValue = toWei(toBN(1));
// Propose a price for OptimisticDepositBox request.const propose = async () => {  const accounts = await web3.eth.getAccounts();  const [deployer] = accounts;  const optimisticOracleContract = await getContract("OptimisticOracle");  const optimisticOracleAddress = await getAddress("OptimisticOracle", chainId);  const optimisticOracle = new web3.eth.Contract(optimisticOracleContract.abi, optimisticOracleAddress);
  // Pull data from the request to use in the proposal  const latestBlock = await web3.eth.getBlockNumber();  const fromBlock = latestBlock - 10000;  const requests = await optimisticOracle.getPastEvents("RequestPrice", { fromBlock: fromBlock });  const lspRequest = requests    .filter((request) => request.returnValues.requester === lspAddress)    .map((request) => {      return {        timestamp: request.returnValues.timestamp,        identifier: request.returnValues.identifier,        ancillaryData: request.returnValues.ancillaryData,      };    });"Proposing a value to the Optimistic Oracle for the price request ...");  await optimisticOracle.methods    .proposePriceFor(      accounts[0],      lspAddress,      lspRequest[0].identifier,      lspRequest[0].timestamp,      lspRequest[0].ancillaryData,      proposedValue    )    .send({ from: deployer });  console.log(`- Proposed a price of ${proposedValue}`);};
// Main script.propose();