Crosschain Transaction

You can perform a crosschain transaction via the DEMOS network with the help of the DEMOS sdk.

Here is how you can send tokens on Sepolia testnet via DEMOS using the sdk:

0. Imports

The following imports will be needed to create the transaction.

import {
  Demos,
  DemosWebAuth,
  prepareXMPayload,
  prepareXMScript,
} from "@kynesyslabs/demosdk/websdk";

import { EVM } from "@kynesyslabs/demosdk/xm-websdk";

1. Creating the EVM payload

You can create the payload for Sepolia via the crosschain module of the sdk as follows:

const sepolia_rpc = "https://rpc.ankr.com/eth_sepolia"
const evm = await EVM.create(sepolia_rpc);
await evm.connectWallet(
  "e0a00e307....." // fill in with your sepolia private key
);

const evm_tx = await evm.preparePay(
    "0xda3ea78Af43E6B1c63A08cD0058973F14e5556b0",
    "0.000000001",
)

The evm_tx will be a signed transaction to move 0.000000001 Sepolia ETH from the connected wallet to0xda3ea78Af43E6B1c63A08cD0058973F14e5556b0.

2. Converting the payload into an XMScript

The XMScript contains information that helps a DEMOS node understand what to do with a signed crosschain payload.

const xmscript = prepareXMScript({
  chain: "eth",
  subchain: "sepolia",
  signedPayloads: [evm_tx],
  type: "pay",
});

The xmscript will be embedded into a DEMOS transaction and sent to the DEMOS network in the upcoming sections.

3. Creating a DEMOS identity

A DEMOS identity is needed to sign the outgoing DEMOS transaction.

const identity = DemosWebAuth.getInstance();
await identity.create();

4. Converting the XMScript to a DEMOS transaction

You can convert the xmscript into a DEMOS transaction by calling prepareXMPayload and passing the xmscript and identity.keypair.

const tx = await prepareXMPayload(xmscript, identity.keypair);

The tx will be a signed DEMOS transaction containing the Sepolia tx.

5. Broadcasting to a DEMOS node

You can now broadcast the transaction using the demos object as shown.

const demos_rpc = "https://demosnode.discus.sh";

const demos = new Demos()
await demos.connect(demos_rpc);
await demos.connectWallet(identity.keypair.privateKey);

// get gas fee information
const validityData = await demos.confirm(tx);
console.log("validityData", validityData);

// execute
const res = await demos.broadcast(validityData);
console.log("res", res);