Development with IMA-SDK and IMA-JS

IMA-SDK is a tool for dApp developers that emulates SKALE Node + IMA env on a single machine for dev purposes. This article will demonstrate how start development using IMA-JS with IMA-SDK.

This article assumes that you’re already have working IMA-SDK with deployed contracts. To setup IMA-SDK refer to this doc.

IMA-JS integration

Once you have IMA-SDK up running, it’s time try some interchain transfers!

In all ima-js code samples we’re assuming that library is already inited. See init instructions here. For the 2 objects usage drop ima. prefix.

1. Connect your chain

First of all you should connect your chain to the Mainnet contracts:

async function chainSetup(ima) {
    const sdkAddress = helper.privateKeyToAddress(ima.mainnet.web3, SDK_PRIVATE_KEY);
    const opts = {
        address: sdkAddress,
        privateKey: SDK_PRIVATE_KEY
    }
    const isChainConnected = await ima.mainnet.isChainConnected(SCHAIN_NAME);
    if (!isChainConnected){
        await ima.connectSchain(SCHAIN_NAME, opts);
    }
}

2. Work with IMA-JS

Once chain is connected you can do anything that you want with your chain! In this example we will transfer ETH from the Mainnet to the SKALE Chain and back.

2.1 Recharge user’s reimbursement wallet

async function reimburseWallet(ima) {
    let testAddress = helper.privateKeyToAddress(ima.schain.web3, TEST_PRIVATE_KEY);
    let txOpts = {
        value: TEST_WEI_REIMBURSEMENT_VALUE,
        address: testAddress,
        privateKey: TEST_PRIVATE_KEY
    };
    await ima.mainnet.reimbursementWalletRecharge(
        SCHAIN_NAME,
        txOpts
    );
}

2.2 Perform transfers

async function ethTransferDemo(ima) {
    const address = helper.privateKeyToAddress(ima.mainnet.web3, TEST_PRIVATE_KEY);
    let txOpts = {
        value: TEST_WEI_TRANSFER_VALUE,
        address: address,
        privateKey: TEST_PRIVATE_KEY
    };

    let mainnetBalanceBefore = await ima.mainnet.ethBalance(address);
    let sChainBalanceBefore = await ima.schain.ethBalance(address);

    await ima.mainnet.depositETHtoSChain(
        SCHAIN_NAME,
        txOpts
    );
    await ima.schain.waitETHBalanceChange(address, sChainBalanceBefore);

    let mainnetBalanceAfterDeposit = await ima.mainnet.ethBalance(address);
    let sChainBalanceAfterDeposit = await ima.schain.ethBalance(address);

    console.log('M -> S transfer complete!');
    console.log('Mainnet balance before deposit: ', mainnetBalanceBefore);
    console.log('SKALE Chain balance before deposit: ', sChainBalanceBefore);
    console.log('Mainnet balance after deposit: ', mainnetBalanceAfterDeposit);
    console.log('SKALE Chain balance after deposit: ', sChainBalanceAfterDeposit);

    let lockedETHAmount = await ima.mainnet.lockedETHAmount(address);

    await ima.schain.withdrawETH(
        TEST_WEI_TRANSFER_VALUE,
        {
            address: address,
            privateKey: TEST_PRIVATE_KEY
        }
    );

    await ima.mainnet.waitLockedETHAmountChange(address, lockedETHAmount);
    await ima.mainnet.getMyEth(
        {
            address: address,
            privateKey: TEST_PRIVATE_KEY
        }
    );

    let mainnetBalanceAfterWithdraw = await ima.mainnet.ethBalance(address);
    let sChainBalanceAfterWithdraw = await ima.schain.ethBalance(address);

    console.log('S -> M transfer complete!');
    console.log('Mainnet balance before withdraw: ', mainnetBalanceAfterDeposit);
    console.log('SKALE Chain balance before withdraw: ', sChainBalanceAfterDeposit);
    console.log('Mainnet balance after withdraw: ', mainnetBalanceAfterWithdraw);
    console.log('SKALE Chain balance after withdraw: ', sChainBalanceAfterWithdraw);
}

async function main() {
    let ima = initIMA();
    const transferValBN = ima.mainnet.web3.utils.toBN(TEST_WEI_TRANSFER_VALUE);

    await chainSetup(ima);
    await reimburseWallet(ima);
    await ethTransferDemo(ima);
}

You can find more IMA-JS docs here.

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