What is the difference between making a transaction using ether js and solidity contract?

Question

I am a beginner learning blockchain development, and I am watching a tutorial on creating a simple dapp that transfers ether to another address, in the tutorial he creates a smart contract called transaction, then he proceeds to make the transaction using ethers.js, then what is the point of creating a contract if I am going to make the transaction using ethers js, and which to choose to use?

Transaction.sol

pragma solidity ^0.8.9;

contract Transaction{
    event Transfer(address from, address receiver, uint amount, string message, uint256 timestamp, string keyword);
    struct TransferStruct{
        address sender;
        address receiver;
        uint amount;
        string message;
        uint256 timestamp;
        string keyword;
    }

    TransferStruct[] transactions;

    function addToBlockchain(address payable receiver, uint amount, string memory message, string memory keyword ) public{
        transactions.push(TransferStruct(msg.sender, receiver, amount, message, block.timestamp, keyword));
        emit Transfer(msg.sender, receiver, amount, message, block.timestamp, keyword);
    }

    function getAllTransactions() public{
        
    }

    function getTransactionCount() public view returns(uint256){

    }
}

Answer 1

A Smart Contract is stored on the blockchain and cannot be changed once deployed on it. It can contain rules or logic on how a transaction can be executed. Through it, we can write certain values to the blockchain and read them, for example.

Ethers.js is an example of a JavaScript library that offers us the ability to call functions from a smart contract. In other words, Ethers.js is used to send a transaction to the blockchain network, which can interact with the smart contract.

In short, if you want to define your own logic on how a transaction will be executed, a smart contract is necessary. Then, you can use Ethers.js to communicate with that smart contract by sending transactions and receiving responses.

In most cases, you will need both.