94 lines
3.1 KiB
JavaScript
94 lines
3.1 KiB
JavaScript
/**
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* ERC-721 Non-Fungible Token Standard
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* See https://eips.ethereum.org/EIPS/eip-721
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* and https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/ERC721.sol
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*
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* This implementation is currently incomplete. It lacks the following:
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* - Token approvals
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* - Operator approvals
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* - Emitting events
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*/
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export class ERC721 {
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constructor(name, symbol) {
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this.name = name;
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this.symbol = symbol;
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this.balances = new Map(); // owner address --> token count
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this.owners = new Map(); // token id --> owner address
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// this.tokenApprovals = new Map(); // token id --> approved addresses
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// this.operatorApprovals = new Map(); // owner --> operator approvals
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this.events = {
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// Transfer: (_from, _to, _tokenId) => {},
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// Approval: (_owner, _approved, _tokenId) => {},
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// ApprovalForAll: (_owner, _operator, _approved) => {},
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};
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}
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incrementBalance(owner, increment) {
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const balance = this.balances.get(owner) ?? 0;
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this.balances.set(owner, balance + increment);
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}
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mint(to, tokenId) {
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console.log('ERC721.mint', { to, tokenId });
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if (this.owners.get(tokenId)) {
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throw new Error('ERC721: token already minted');
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}
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this.incrementBalance(to, 1);
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this.owners.set(tokenId, to);
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}
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burn(tokenId) {
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const owner = this.owners.get(tokenId);
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this.incrementBalance(owner, -1);
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this.owners.delete(tokenId);
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}
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balanceOf(owner) {
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if (!owner) {
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throw new Error('ERC721: address zero is not a valid owner');
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}
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return this.balances.get(owner) ?? 0;
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}
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ownerOf(tokenId) {
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const owner = this.owners.get(tokenId);
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if (!owner) {
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throw new Error(`ERC721: invalid token ID: ${tokenId}`);
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}
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return owner;
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}
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transfer(from, to, tokenId) {
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console.log('ERC721.transfer', { from, to, tokenId });
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const owner = this.owners.get(tokenId);
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if (owner !== from) {
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throw new Error(`ERC721: transfer from incorrect owner ${from}; should be ${owner}`);
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}
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this.incrementBalance(from, -1);
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this.incrementBalance(to, 1);
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this.owners.set(tokenId, to);
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}
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/// @notice Enable or disable approval for a third party ("operator") to manage
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/// all of `msg.sender`'s assets
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/// @dev Emits the ApprovalForAll event. The contract MUST allow
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/// multiple operators per owner.
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/// @param _operator Address to add to the set of authorized operators
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/// @param _approved True if the operator is approved, false to revoke approval
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// setApprovalForAll(_operator, _approved) {}
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/// @notice Get the approved address for a single NFT
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/// @dev Throws if `_tokenId` is not a valid NFT.
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/// @param _tokenId The NFT to find the approved address for
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/// @return The approved address for this NFT, or the zero address if there is none
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// getApproved(_tokenId) {}
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/// @notice Query if an address is an authorized operator for another address
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/// @param _owner The address that owns the NFTs
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/// @param _operator The address that acts on behalf of the owner
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/// @return True if `_operator` is an approved operator for `_owner`, false otherwise
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// isApprovedForAll(_owner, _operator) {}
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}
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