NFT Minting and Burning Mechanics 3 — Questions and Answers
Question 1: In ERC-1155, which function mints a quantity of a fungible token id to an address?
- _mint(to, id, amount, data) (Correct answer)
- _mint(to, tokenId)
- safeTransferFrom(from, to, id)
- _burnBatch(from, ids, amounts)
Correct answer: _mint(to, id, amount, data)
ERC-1155 _mint takes an id, an amount, and a data parameter for batched/semi-fungible tokens.
Question 2: What is the main gas advantage of ERC-1155 _mintBatch over multiple ERC-721 mints?
- Multiple token ids are minted in a single transaction (Correct answer)
- It skips emitting any events
- It removes the need for approvals forever
- It avoids storing balances on-chain
Correct answer: Multiple token ids are minted in a single transaction
Batch minting creates several token ids in one call, saving per-transaction overhead.
Question 3: Which event does ERC-1155 emit for a single burn operation?
- TransferSingle with the 'to' field as the zero address (Correct answer)
- Transfer with tokenId
- BurnSingle
- ApprovalForAll
Correct answer: TransferSingle with the 'to' field as the zero address
ERC-1155 burns emit TransferSingle with the destination set to address(0).
Question 4: In ERC-1155, what must hold true for _burn(from, id, amount) to succeed?
- The 'from' balance for that id must be at least 'amount' (Correct answer)
- The token must be non-fungible
- The caller must be the contract deployer
- The amount must equal one
Correct answer: The 'from' balance for that id must be at least 'amount'
Burning reverts if the holder's balance for the id is less than the amount being burned.
Question 5: When using lazy minting, when is the NFT actually written to the blockchain?
- At the time of the first purchase or claim (Correct answer)
- At the moment of contract deployment
- When metadata is uploaded to IPFS
- Never; it stays off-chain permanently
Correct answer: At the time of the first purchase or claim
Lazy minting defers the on-chain mint until a buyer triggers it, shifting gas to the buyer.
Question 6: What signed data structure typically authorizes a lazy mint via voucher?
- An EIP-712 typed signature from the creator (Correct answer)
- A raw private key embedded in the contract
- A Merkle root with no signature
- A plaintext password hash
Correct answer: An EIP-712 typed signature from the creator
Lazy mint vouchers are commonly authorized with EIP-712 typed-data signatures.
Question 7: Why is _mintBatch's array length validation important?
- The ids and amounts arrays must be equal length to map correctly (Correct answer)
- It determines the token's resale price
- It sets the royalty percentage
- It encrypts the metadata
Correct answer: The ids and amounts arrays must be equal length to map correctly
Mismatched ids and amounts array lengths would corrupt balance assignment, so they must match.
NFT Minting and Burning Mechanics 3
In ERC-1155, which function mints a quantity of a fungible token id to an address?