announcement.ts

import { Contract, ElectrumNetworkProvider } from 'cashscript';
import { compileFile } from 'cashc';
import { stringify } from '@bitauth/libauth';
import { URL } from 'url';

// Compile the Announcement contract to an artifact object
const artifact = compileFile(new URL('announcement.cash', import.meta.url));

// Initialise a network provider for network operations on MAINNET
const addressType = 'p2sh20';
const provider = new ElectrumNetworkProvider();

// Instantiate a new contract using the compiled artifact and network provider
// AND providing the constructor parameters (none)
const contract = new Contract(artifact, [], { provider, addressType });

// Get contract balance & output address + balance
console.log('contract address:', contract.address);
console.log('contract balance:', await contract.getBalance());
console.log('contract opcount:', contract.opcount);
console.log('contract bytesize:', contract.bytesize);

// Send the announcement. Trying to send any other announcement will fail because
// the contract's covenant logic. Uses a hardcoded fee and minChange so that
// change is only sent back to the contract if there's enough leftover
// for another announcement.
const str = 'A contract may not injure a human being or, through inaction, allow a human being to come to harm.';
const tx = await contract.functions
  .announce()
  .withOpReturn(['0x6d02', str])
  .withHardcodedFee(1000n)
  .withMinChange(1000n)
  .send();

console.log('transaction details:', stringify(tx));