Crowdfunder (Solidity Smart Contract w/ Hardhat)

• this is my personal implementation of a crowfunder project (similar to kickstarter)

Overview

The purpose of this project is the following:

• Build a smart contract that allows creators to register their projects.
• Other people can contribute ETH to that project.
• Once the goal has been met, the creators can withdraw the funds.
• When someone contributes 1 ETH, they receive a contributor badge NFT, which is tradable.

Main Commands (to see tests)

• npm i
• npx hardhat compile
• npx hardhat test

Technical Implementation

• I split the logic into 2 contracts Project.sol and ProjectFactory.sol. I am using factory pattern here.
• Every time a new project is registered, I create a new contract in Project using ProjectFactory.

More Details

I added comments within contract where each of these features is added

1. The smart contract is reusable; multiple projects can be registered and accept ETH concurrently.

• (1a) Specifically, you should use the factory contract pattern.

2. The goal is a preset amount of ETH.

• (2a) This cannot be changed after a project gets created.

3. Regarding contributing:

• (3a) The contribute amount must be at least 0.01 ETH.
• (3b) There is no upper limit.
• (3c) Anyone can contribute to the project, including the creator.
• (3d) One address can contribute as many times as they like.
• (3e) No one can withdraw their funds until the project either fails or gets cancelled.

4. Regarding contributer badges:

• (4a) An address receives a badge if their total contribution is at least 1 ETH.
• (4b) One address can receive multiple badges, but should only receive 1 badge per 1 ETH.
• (4c) Each project should use its own NFT contract.

5. If the project is not fully funded within 30 days:

• (5a) The project goal is considered to have failed.
• (5b) No one can contribute anymore.
• (5c) Supporters get their money back.
• (5d) Contributor badges are left alone. They should still be tradable.

6. Once a project becomes fully funded:

• (6a) No one else can contribute (however, the last contribution can go over the goal).
• (6b) The creator can withdraw any amount of contributed funds.

7. The creator can choose to cancel their project before the 30 days are over, which has the same effect as a project failing.