An ICO contract for SpaceCoin, an ERC20 token that implements a toggleable token transfer tax. The ICO aims to raise 30,000ETH through the sale of SpaceCoin over three phases:

1. Seed Phase: 1.5k individual contribution max. 15k total.
2. General Phase: 1k indidivual contribution max. 30k total.
3. Open Phase: No individual contribution limits. 30k total.

• 500k max supply
• 2% toggable (default off) tx fee that goes to treasury.

• Run all tests using npx hardhat test
• The contract is deployed on Goerli Testnet at 0x3C681Ca14A58a054513786BF91b5C112684D50c1 and verified on etherscan.io.
• My design is as follows:
  • Two contracts SpaceCoin and SpaceCoinICO, both of which are "Ownable" by an address provided in the ICO constructor. The ICO will instantiate a new instance of the token contract, at which point the entire supply is minted. 150k for the ICO contract, 350k for the treasury.
  • SpaceCoin extends to OZ's ERC20 contract and is kept as minimal as possible.
    • It overrides the ERC20 transfer() function to allow for transfer tax collection (if active).
    • The manager of contract toggles the tax on or off.
    • It uses default ERC20 values with 18 decimal places.
  • SpaceCoinICO encapsulates the rest of the features of the project.
    • Tokens are purchased through the buyTokens() function, which is either called directly or indirectly through the receive(), when investors directly send money to the contract.
    • All token sales are recorded in the contributions mapping, as well as tokensToCollect mapping. The latter is used for contributions that happen pre-Open phase.
    • Once ICO reaches Open phase, investors can use redeemTokens() to collect any tokens that have been purchased pre-Open phase. Investors who buy tokens in Open phase will automatically receive SPC.
    • currentPhase enum tracks the ICO progress, which can only be adjusted by the manager manually.
    • Whitelist feature implemented with the whitelist mapping. The manager can only add addresses to the whitelist.

I've implemented a frontend using parcel. On my system, the server instance is at http://localhost:5000.

cd frontend
npx parcel src/index.html --no-cache