Examples

Interacting with cGold & cDollar

celo-blockchain has two initial coins: cGold and cDollar (stableToken). Both implement the ERC20 standard, and to interact with them is as simple as:

const goldtoken = await kit.contract.getGoldToken()
const balance = await goldtoken.balanceOf(someAddress)

To send funds:

const oneGold = kit.web3.utils.toWei('1', 'ether')
const tx = await goldtoken.transfer(someAddress, oneGold).send({
from: myAddress,
})
const hash = await tx.getHash()
const receipt = await tx.waitReceipt()

To interact with cDollar, is the same but with a different contract:

const stabletoken = await kit.contract.getStableToken()

Interacting with Other Contracts

Apart from GoldToken and StableToken, there are many core contracts.

For the moment, we have contract wrappers for:

  • Exchange (Uniswap kind exchange between Gold and Stable tokens)

  • Validators

  • LockedGold

In the following weeks, we will add some wrappers for all other contracts

Accessing web3 contract wrappers

Some user might want to access web3 native contract wrappers.

To do so, you can:

const web3Exchange = await kit._web3Contracts.getExchange()

We expose native wrappers for all Celo core contracts.

A Note About Contract Addresses

Celo Core Contracts addresses, can be obtained by looking at the Registry contract. That's actually how kit obtain them.

We expose the registry api, which can be accessed by:

const goldTokenAddress = await kit.registry.addressFor(CeloContract.GoldToken)

Sending Custom Transactions

Celo transaction object is not the same as Ethereum's. There are two new fields present:

  • gasCurrency (address of the ERC20 contract to use to pay for gas)

  • gasFeeRecipient (address of the beneficiary for the gas, the full node)

This means that using web3.eth.sendTransaction or myContract.methods.transfer().send() should be avoided.

Instead, kit provides an utility method to send transaction in both scenarios. If you use contract wrappers, there is no need to use this.

For a raw transaction:

const tx = kit.sendTransaction({
from: myAddress,
to: someAddress,
value: oneGold,
})
const hash = await tx.getHash()
const receipt = await tx.waitReceipt()

When interacting with a web3 contract object:

const goldtoken = await kit._web3Contracts.getGoldToken()
const oneGold = kit.web3.utils.toWei('1', 'ether')
const txo = await goldtoken.methods.transfer(someAddress, oneGold)
const tx = await kit.sendTransactionObject(txo, { from: myAddress })
const hash = await tx.getHash()
const receipt = await tx.waitReceipt()

Debugging

If you need to debug kit, we use the well known debug node library.

So set the environment variable DEBUG as:

DEBUG="kit:*,