Ethereum: How to solve invalid input params issue for uniswap v2 router ‘addLiquidity’ method

Fixing the “Invalid Input Parameters” Issue in the “addLiquidity” Method Using Uniswap v2 Router with Wagmi and Ethers

Uniswap v2 is a popular decentralized exchange (DEX) protocol that allows users to trade cryptocurrencies across multiple blockchain networks. One of the main features of Uniswap is its liquidity pool management, which is based on the “addLiquidity” method provided by the router. However, this method can cause errors if certain parameters are not properly validated or passed as arguments.

In this article, we will delve into the details of the addLiquidity method and explore the potential issues that can arise from improper parameter usage.

The “addLiquidity” Method

The “addLiquidity” method is used to increase the liquidity of the Uniswap pool. It uses the following parameters:

• “input”: The input quantity of one of the two traded tokens.

• “quantities”: A dictionary containing the output quantities of each token sent as a result of the trade.

• liquidity: An optional parameter that specifies the liquidity providers (LPs) participating in the trade.

Invalid parameter usage

If any of these parameters are not validated or cannot be passed properly, the addLiquidity method may throw an error. Here are some possible issues in detail:

• Missing or invalid input: If the input quantity is missing or invalid, the method returns an error.

• Invalid quantities' dictionary: The output quantities must match the expected values ​​specified in the Uniswap protocol. Any deviations may lead to errors.

• Invalid or incorrectliquidityparameter: If the liquidity providers are not configured properly or do not have sufficient resources, the method may throw an error.

Error Handling and Debugging

If errors occur in the addLiquidity method, it is important to handle them effectively. Here are some steps you can take:

• Check the error message: The error message contains valuable information about what happened.

• Check the parameter values: Make sure that all parameters have valid values ​​and follow the expected formats.

• Check the “amounts” dictionary: Compare the output quantities with the values ​​specified in the Uniswap protocol.

Sample code with correct parameter usage

To demonstrate how to resolve common issues, let’s look at a sample code snippet using Wagmi and Ethers:

import { useContract } from 'wagmi';
import { addLiquidity } from './uniswapRouter';
const LUCI = {
Address: "0x...",
TokenIn: 'LUL',
TokenOut: 'DOL',
};
async function main() {
try {
const liquidity = wait useContract(addLiquidity, LUCI);
console.log('Liquidity added:', liquidity);
// Check parameter values
wait(liquidity.input).equals(10); // Input quantity in LUL
// Compare output quantities with Uniswap protocol
if (liquidity.quantities.LUL !== 2) {
throw new Error(Expected quantity of LUL: 2, got ${liquidity.quantities.LUL}`);
}
} catch (error) {
console.error('Error:', error);
}
}
Main();

Conclusion

In order to ensure that your Uniswap v2 router implementation is robust and error-free, it is important to properly validate parameter values ​​and compare them to expected formats. By following best practices for parameter handling and debugging, you can identify and resolve issues resulting from invalid or missing parameters.

Be sure to check the error message and verify the parameter values ​​if errors occur in the "addLiquidity" method. Additionally, check the "amounts" dictionary to ensure that it matches the expected output quantities specified in the Uniswap protocol.