NFT Token Standards (ERC-721/1155) 2

Question 1

In ERC-721, which function returns the address that owns a given tokenId?

Accepted Answer

ownerOf(uint256)

Answer

ownerOf(tokenId) returns the current owner address of that specific NFT.

Question 2

What does ERC-721's safeTransferFrom do that transferFrom does not?

Accepted Answer

Checks the recipient can receive ERC-721 via onERC721Received

Answer

safeTransferFrom verifies a contract recipient implements onERC721Received to avoid trapping tokens.

Question 3

ERC-1155 supports which type of token in a single contract?

Accepted Answer

Both fungible and non-fungible

Answer

ERC-1155 is a multi-token standard handling fungible, non-fungible, and semi-fungible tokens together.

Question 4

Which ERC-1155 function transfers multiple token types at once?

Accepted Answer

safeBatchTransferFrom

Answer

safeBatchTransferFrom moves arrays of ids and amounts in one call to save gas.

Question 5

What standard is used to detect whether a contract implements ERC-721?

Accepted Answer

ERC-165 supportsInterface

Answer

ERC-165's supportsInterface lets callers query whether a contract implements a given interface id.

NFT Development Practice Test