The Melon Bot's Price Query

MelonBot.getPrice.ts

  public async getPrice(baseCurrency: TokenDefinition, quoteCurrency: TokenDefinition, baseQuantity: BigNumber) {
    // Every uniswap exchange is WETH/someToken, and identified by the non-weth token
    const exchangeToken = baseCurrency.symbol === 'WETH' ? quoteCurrency : baseCurrency;

    // call the method to find the address
    const exchangeAddress = await this.uniswapFactoryContract.getExchange(exchangeToken.address);

    // instantiate the exchange contract
    const exchange = new UniswapExchange(this.environment, exchangeAddress);

    // call the correct method to get the price. If the base currency is WETH, you want to go ETH => token and vice versa
    const quoteQuantity =
      baseCurrency.symbol === 'WETH'
        ? await exchange.getEthToTokenInputPrice(baseQuantity) // quantity passed is in WETH if you're trying to sell WETH for MLN
        : await exchange.getTokenToEthInputPrice(baseQuantity); // quantity passed is in MLN if you're trying to sell MLN for WETH

    // price will be important if you're doing any TA. My magicFunction doesn't use it but I've included it anyway.
    const priceInBase = quoteQuantity.dividedBy(baseQuantity);
    const priceInQuote = new BigNumber(1).dividedBy(priceInBase);

    return {
      baseCurrency: baseCurrency,
      quoteCurrency: quoteCurrency,
      priceInBase: priceInBase,
      priceInQuote: priceInQuote,
      sizeInBase: baseQuantity,
      sizeInQuote: quoteQuantity,
      exchangeAddress: exchangeAddress,
    } as PriceQueryResult;
  }