A JavaScript library for element.market: buy, sell, make offer on any NFTs. With Element.js, you can easily build yourown NFT marketplace. Trade ERC721 or ERC1155 items. You don't have to deploy your own smart contracts or off-chain orderbooks.

Published on GitHub and npm

Synopsis
Installation
Getting Started
Advanced
Learning More

Synopsis

This is the JavaScript SDK for element.market, a marketplace for NFTs.

It allows developers to access the official orderbook, filter it, create buy orders (offers), create sell orders (listings), and complete trades programmatically.

You get started by requesting an API key and instantiating your own sdk. Then you can create orders off-chain or fulfill orders on-chain.

Installation

Install element-js-sdk, in your project, run:

npm install --save element-js-sdk

If your project run in browser environment, you need install crypto-browserify, stream-browserify, buffer, and config webpack.config.js:

#install crypto-browserify, stream-browserify, buffer
npm install --save crypto-browserify
npm install --save stream-browserify
npm install --save buffer

#config webpack.config.js
module.exports = function (webpackEnv) {
  ...
  return {
    ...
    resolve: {
        ...
        fallback: {
            crypto: require.resolve("crypto-browserify"),
            stream: require.resolve("stream-browserify"),
            buffer: require.resolve('buffer/'),
        },
    },
    ...
    plugins: [
        ...
        new webpack.ProvidePlugin({
            Buffer: ['buffer', 'Buffer'],
        }),
    ],
  }
};

Getting Started

To get started, first request an API key here.

Then, create a new ElementJS client, using your ethers web3Provider or signer:

Note that, the default web3Provider does not check for network timeout. To do that, refer to the TimeoutWeb3Provider.

import { ElementSDK, Network } from 'element-js-sdk'
import { ethers } from 'ethers'

// In Browser
// https://docs.ethers.io/v5/getting-started/#getting-started--connecting-rpc
// A Web3Provider wraps a standard Web3 provider, which is what MetaMask injects as window.ethereum into each page.
// const signerOrProvider = new ethers.providers.Web3Provider(window.ethereum);
const signerOrProvider = new TimeoutWeb3Provider(window.ethereum);

// In Node.js
// https://docs.ethers.io/v5/api/signer/
const jsonRpcProvider = new ethers.providers.JsonRpcProvider(rpcUrl);
const signerOrProvider = new ethers.Wallet(privateKey, jsonRpcProvider);

const sdk = new ElementSDK({
  // Supported networks: Network.ETH, Network.BSC, Network.Polygon, Network.Avalanche
  networkName: Network.ETH,
  isTestnet: false,
  apiKey: YOUR_API_KEY,
  signer: signerOrProvider
});

Note that the operations: sign orders erc20.approve erc721.setApprovalForAll erc1155.setApprovalForAll is done inside this sdk.

Making Listings

To sell a bulk of ERC-721 assets, call makeERC721SellOrders.

const r = await sdk.makeERC721SellOrders({
  items: [{
    erc721TokenAddress: tokenAddress1,
    erc721TokenId: tokenId1,
    paymentTokenAmount: '1100000000000000000'
  }, {
    erc721TokenAddress: tokenAddress2,
    erc721TokenId: tokenId2,
    paymentTokenAmount: 1200000000000000000
  }, {
    erc721TokenAddress: tokenAddress3,
    erc721TokenId: tokenId3,
    paymentTokenAmount: 1.3e18
  }]
});
console.log("succeedList, ", r.succeedList);
console.log("failedList, ", r.failedList);

To sell an asset, call makeSellOrder.

const order = await sdk.makeSellOrder({
  assetAddress: tokenAddress,
  assetId: tokenId,
  paymentTokenAmount: '2000000000000000000'
});

Note that the default assets is ERC-721. For ERC-1155 assets, you should set assetSchema to AssetSchema.ERC1155 and pass a quantity:

const order = await sdk.makeSellOrder({
  // ...
  assetSchema: AssetSchema.ERC1155,
  quantity: 10000,
});

The default payment token is native token(e.g. ETH on ether chain), if use an ERC20 token, you can set paymentToken to an ERC20 token address.

const order = await sdk.makeSellOrder({
  // ...
  paymentToken: paymentToken
});

The default expiration time is 7 days, you can set expirationTime to specify another expiration time.

// Note that we convert from the JavaScript timestamp (milliseconds to seconds):
const expirationTime = Math.round(Date.now() / 1000 + 60 * 60 * 24);
const order = await sdk.makeSellOrder({
  // ...
  expirationTime: expirationTime
});

Making Offers

You can make offers on an asset:

const order = await sdk.makeBuyOrder({
  assetId: assetId,
  assetAddress: assetAddress,
  paymentTokenAmount: '3000000000000000000'
});

Note that make offers aren't supported with the native token, so you have to use an ERC20 token, or wrapped native token if none is specified.

Making Collection-Based Offers

You can make offers for any NFT from a specific collection.

const order = await sdk.makeBuyOrder({
  // Note that don't specify the `assetId`
  assetAddress: assetAddress,
  // Value of the order, in units of the payment token (or wrapped native token if none is specified).
  paymentTokenAmount: '3000000000000000000'
});

Fetching Orders

To fetching orders of the element market, call queryOrders:

import { ElementSDK } from 'element-js-sdk'

const orders = await sdk.queryOrders({
  asset_contract_address: assetAddress,
  token_ids: [assetId]
});

The api documentation is here, and the example is here.

Fill Orders

To buy a bulk of NFTs, call batchBuyWithETH:

const orders = await sdk.queryOrders({ ... });
const transaction = await sdk.batchBuyWithETH({
  orders: orders
});
console.log("tx.hash: ", transaction.hash);

// wait for transaction completed.
const receipt = await transaction.wait();
console.log("completed，receipt: ", receipt);

// getBoughtAssets
const assets = sdk.getBoughtAssets(receipt)
console.log('assets: ', assets)

To buy or sell a NFT, call fillOrder:

const orders = await sdk.queryOrders({ ... });
const order = orders[0]; // select an order
const transaction = await sdk.fillOrder({
  order: order
});
console.log("tx.hash: ", transaction.hash);
const receipt = await transaction.wait();
console.log("completed，receipt: ", receipt);

Note that if the order is a Collection-Based Offer, you need specify the assetId:

const transaction = await sdk.fillOrder({
  order: order,
  assetId: assetId
});
const receipt = await transaction.wait();
console.log("completed.");

For the ERC-1155 asset order, the default quantity is all the remaining quantity. You can also set the quantity if needed. To do that, it's just call like below:

const quantity = '5000';
const transaction = await sdk.fillOrder({
  order: order,
  quantity: quantity
});
const receipt = await transaction.wait();
console.log("completed");

Cancel Orders

To cancel an order, call cancelOrder.

const orders = await sdk.queryOrders({ ... });
const order = orders[0]; // select an order
const transaction = await sdk.cancelOrder({
  order: order
});
const receipt = await transaction.wait()
console.log("completed")

To cancel a bulk of orders, call cancelOrders:

const orders = await sdk.queryOrders({ ... });
const r = await sdk.cancelOrders({
  orders: orders
})
for (const info of r.succeedTransactions) {
  console.log('tx.hash: ', info.transaction.hash)
  const receipt = await info.transaction.wait()
  console.log('completed， receipt: ', receipt)
  console.log('orders: ', info.orders)
}

To cancel all orders of the signer, call cancelAllOrdersForSigner:

const transaction = await sdk.cancelAllOrdersForSigner({
  // Supported Standard: Standard.ElementEx, Standard.Seaport, Standard.LooksRare
  standard: Standard.ElementEx
});
const receipt = await transaction.wait()
console.log("completed")

Encode Trade Data

If you want to get TradeData, call encodeTradeData.

const orders = await sdk.queryOrders({ ... });
const tradeData = await sdk.encodeTradeData({
  orders: orders,
  taker: accountAddress
});
console.log("tradeData: ", tradeData);

// sendTransaction
const signer = await getEthersSigner()
const transaction = await signer.sendTransaction({
  to: tradeData.toContract,
  data: tradeData.data,
  value: tradeData.payableValue
})

// wait for transaction completed.
const receipt = await transaction.wait();
console.log("completed，receipt: ", receipt);

// getBoughtAssets
const assets = sdk.getBoughtAssets(receipt)
console.log('assets: ', assets)

Note that the taker is optional, and the default taker is sdk.signer.

Advanced

Interested in purchasing for scheduling future orders, or private auctions, element.js can help with that.

User-Defined GasPrice

You can set maxFeePerGas and maxPriorityFeePerGas(EIP-1559), or just set gasPrice.

const transaction = await sdk.fillOrder({
  order: order,
  maxFeePerGas: 21e9,       // string or number.
  maxPriorityFeePerGas: 2e9 // string or number.
});
const receipt = await transaction.wait();
console.log("completed");

const transaction = await sdk.fillOrder({
  order: order,
  gasPrice: '30000000000', // string or number.
});
const receipt = await transaction.wait();
console.log("completed");

Scheduling Future Listings

You can create sell orders that aren't fulfillable until a future date. Just pass in a listingTime (a UTC timestamp in seconds) to your sdk instance:

const order = await sdk.makeSellOrder({
  assetId: assetId,
  assetAddress: assetAddress,
  startTokenAmount: 3e19,
  listingTime: Math.round(Date.now() / 1000 + 60 * 60 * 24) // One day from now
});

Private Auctions

Now you can make offers and listings that can only be filled by an address of your choosing. This allows you to negotiate a price in some channel and sell for your chosen price on element.market, without having to trust that the counterparty will abide by your terms!

Here's an example of listing a Decentraland parcel for 3 ETH with a specific buyer address allowed to take it. No more needing to worry about whether they'll give you enough back!

// Address allowed to buy from you
const takerAddress = "0x123..."
const order = await sdk.makeSellOrder({
  takerAddress: takerAddress,
  assetId: assetId,
  assetAddress: assetAddress,
  startTokenAmount: 3e19
});

Learning More

The examples are here.

The documentation for developer is available here.

If you need extra help, support is free! You can email us api@element.market.