composable-challenge

Task

The task is to layer on the composability logic from the EIP-998 ontop of the pre-existing ERC721 contract in the repo, with a focus on composing an ERC20 token within an NFT, by following the Top Down ERC20 variant of the ERC-998 standard. The objective of this task it to have Composable contract which can perform the following:

• Mint an NFT and some ERC20 token
• Compose the minted ERC20 token within an NFT
• Query the ERC20 token balance for a given NFT
• Allow addresses only send the tokens that they own

Solution Analysis

I took the following steps to solve this test:

• Started out by reading the EIP to understand the architecture of a Composable NFT
• I spent some time looking at the original implementation, and some more time going through the test to understand how how to interact with the contract
• Focused on ERC721 and ERC20 Top-Down Composable to understand how to Transfer ERC721 and ERC20 tokens to top-down composable contract.
• To transfer an ERC20 token to a Composable NFT contract, I went with the second approach and used the getERC20 function from the original implementation.
• I completed the MyComposableNFT contract using some of the functions from the original implementation such as erc20Received and getERC20.
• I tested the contract by following a following the flow:
  • Mint ERC721 and ERC20 tokens from Composable and Token contract respectively
  • Transfer some of the minted ERC20 tokens to Composable 0
  • Transfer half of Composable O's tokens to another address
  • Check in all cases that no one can steal funds that are not theirs
  • Fetch and verify all balances

Install dependencies

yarn

Compile

yarn compile

Test (truffle test files supported in test/)

yarn test