Solidity factory smart contract

I will be showing you how to set up a factory smart contract that you or any other person can use to create different instances of a functional app.

I believe you already know the basic syntax of solidity. If not You can read this article where I explain the basics of solidity (https://shorturl.at/ayEV4).

First of all, we will create a new contract that will act as the child

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.0;
contract CounterApp {
    uint public number = 1; //This sets the initial value of our counter to 1. The public visibility identifier provides us with a getter function automatically

    function incrementCounter () public {
        number += 1 // This increases the number of our counter by 1
    }

    function decrementCounter () public {
        number -= 1 // This decreases the number of our counter by 1
    }
 }

So the above solidity code is a counter contract code that creates a counter app that keeps track of our counter (which can be decreased or increased).

We will now create a factory contract that helps create different instances of our counter app. Hence helping others have their counter app.

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.0;

import "./CounterApp.sol"; //This imports the Counter app 
contract CounterAppFactory {

function createCounter () external returns (CounterApp counter){
    counter = new CounterApp(); //This creates an instance of your counterApp and returns an address for you to use and interact with your counter app interface
    }
}

With the above code, we have created a factory where instances of a counter app can be created. Hence providing a different counter app with their storage to whoever calls the createCounter function.

Let's test out our factory code using Remix IDE

First of all, we deploy our Factory smart contract which provides us with the function to create different instances of our counter app.

The create function provides us with an address (decoded output), which we can use as our counter app.

With the instance address, we then fetch the contract using At Address, which then enables us to have our counter app (increase counter, decrease counter and get counter value).

So with this knowledge you can create a smart contract and create a factory to produce different instance of your contract. Instead of coding different instances of your smart contract.

Creating a Factory Contract