A JavaScript SDK for Ethereum and the Compound Protocol.
npm install @meterio/compound-js
A JavaScript SDK for Ethereum and the Compound Protocol. Wraps around Ethers.js. Works in the web browser and Node.js.
This SDK is in open beta, and is constantly under development. USE AT YOUR OWN RISK.
JSON RPC based Ethereum read and write.
``js
const Compound = require('@compound-finance/compound-js'); // in Node.js
const cUsdtAddress = Compound.util.getAddress(Compound.cUSDT);
(async function() {
let supplyRatePerBlock = await Compound.eth.read(
cUsdtAddress,
'function supplyRatePerBlock() returns (uint)',
[], // [optional] parameters
{} // [optional] call options, provider, network, ethers.js "overrides"
);
console.log('USDT supplyRatePerBlock:', supplyRatePerBlock.toString());
})().catch(console.error);
`
`js
const toAddress = '0xa0df350d2637096571F7A701CBc1C5fdE30dF76A';
(async function() {
const trx = await Compound.eth.trx(
toAddress,
'function send() external payable',
[],
{
value: Compound._ethers.parseEther('1.0'), // 1 ETH
provider: window.ethereum, // in a web browser
}
);
const toAddressEthBalance = await Compound.eth.getBalance(toAddress);
})().catch(console.error);
`
Simple methods for using the Compound protocol.
`js
const compound = new Compound(window.ethereum); // in a web browser
// Ethers.js overrides are an optional 3rd parameter for supply
// const trxOptions = { gasLimit: 250000, mantissa: false };
(async function() {
console.log('Supplying ETH to the Compound protocol...');
const trx = await compound.supply(Compound.ETH, 1);
console.log('Ethers.js transaction object', trx);
})().catch(console.error);
`
Web Browser
`html
`
Node.js
`
npm install @compound-finance/compound-js
`js
const Compound = require('@compound-finance/compound-js');
// or, when using ES6
import Compound from '@compound-finance/compound-js';
`
See the docblock comments above each function definition or the official Compound.js Documentation.
The following are valid Ethereum providers for initialization of the SDK.
`js
var compound = new Compound(window.ethereum); // web browser
var compound = new Compound('http://127.0.0.1:8545'); // HTTP provider
var compound = new Compound(); // Uses Ethers.js fallback mainnet (for testing only)
var compound = new Compound('ropsten'); // Uses Ethers.js fallback (for testing only)
// Init with private key (server side)
var compound = new Compound('https://mainnet.infura.io/v3/_your_project_id_', {
privateKey: '0x_your_private_key_', // preferably with environment variable
});
// Init with HD mnemonic (server side)
var compound = new Compound('mainnet' {
mnemonic: 'clutch captain shoe...', // preferably with environment variable
});
`
Names of contracts, their addresses, ABIs, token decimals, and more can be found in /src/constants.ts. Addresses, for all networks, can be easily fetched using the getAddress function, combined with contract name constants.
`js
console.log(Compound.DAI, Compound.ETH, Compound.cETH);
// DAI, ETH, cETH
const cUsdtAddress = Compound.util.getAddress(Compound.cUSDT);
// Mainnet cUSDT address. Second parameter can be a network like 'ropsten'.
`
Parameters of number values can be plain numbers or their scaled up mantissa values. There is a transaction option boolean to tell the SDK what the developer is passing.
`js
// 1 Dai
await compound.borrow(Compound.DAI, '1000000000000000000', { mantissa: true });
// mantissa defaults to false if it is not specified or if an options object is not passed`
await compound.borrow(Compound.DAI, 1, { mantissa: false });
Each method that interacts with the blockchain accepts a final optional parameter for overrides, much like Ethers.js overrides.
`jsCompound._ethers.utils.parseUnits('10.0', 'gwei')
// The options object itself and all options are optional
const trxOptions = {
mantissa, // Boolean, parameters array arg of 1 ETH would be '1000000000000000000' (true) vs 1 (false)
abi, // Definition string or an ABI array from a solc build
provider, // JSON RPC string, Web3 object, or Ethers.js fallback network (string)
network, // Ethers.js fallback network provider, "provider" has precedence over "network"
from, // Address that the Ethereum transaction is send from
gasPrice, // Ethers.js override
gasLimit, // Ethers.js override - see https://docs.ethers.io/ethers.js/v5-beta/api-contract.html#overrides
value, // Number or string
data, // Number or string
chainId, // Number
nonce, // Number
privateKey, // String, meant to be used with (server side)Compound.eth.trx
mnemonic, // String, meant to be used with (server side)`
};
The Compound API is accessible from Compound.js. The corresponding services are defined in the api namespace on the class.
- Compound.api.account
-
-
-
The governance method requires a second parameter (string) for the corresponding endpoint shown in the documentation.
- proposals
-
-
Here is an example for using the account endpoint. The network parameter in the request body is optional and defaults to mainnet.
`js
const main = async () => {
const account = await Compound.api.account({
"addresses": "0xB61C5971d9c0472befceFfbE662555B78284c307",
"network": "ropsten"
});
let daiBorrowBalance = 0;
if (Object.isExtensible(account) && account.accounts) {
account.accounts.forEach((acc) => {
acc.tokens.forEach((tok) => {
if (tok.symbol === Compound.cDAI) {
daiBorrowBalance = +tok.borrow_balance_underlying.value;
}
});
});
}
console.log('daiBorrowBalance', daiBorrowBalance);
}
main().catch(console.error);
`
Tests are available in ./test/*.test.js. The tests are configured in ./test/index.js. Methods are tested using a forked chain using ganache-core. A JSON RPC provider URL needs to be configured as an environment variable before running the tests (MAINNET_PROVIDER_URL). Archive state must be available to run the tests. For free archive node access, get a provider URL from Alchemy.
`Run all tests
npm test
Build for Node.js & Web Browser
git clone git@github.com:compound-finance/compound-js.git
cd compound-js/
npm install
npm run build
$3
html
`$3
js
// Local build (do npm install first)
const Compound = require('./dist/nodejs/index.js');// Public NPM build
const Compound = require('@compound-finance/compound-js');
``