Getting Started

Installing the CashScript compiler

The command line CashScript compiler cashc can be installed from NPM.

npm install -g cashc

Installing the JavaScript SDK

The JavaScript SDK can be installed into your project with NPM.

npm install cashscript

Caution: CashScript only offers a JavaScript SDK, but CashScript contracts can be integrated into other languages as well. Because there are no ready-to-use SDKs available for them, this is considered advanced usage, and it is recommended to use the JavaScript SDK.

Writing your first smart contract

There are some examples available on the Examples page, that can be used to take inspiration from. Further examples of the JavaScript integration can be found on GitHub. A simple example is included below.

pragma cashscript ^0.7.0;

contract TransferWithTimeout(pubkey sender, pubkey recipient, int timeout) {
    // Allow the recipient to claim their received money
    function transfer(sig recipientSig) {
        require(checkSig(recipientSig, recipient));
    }

    // Allow the sender to reclaim their sent money after the timeout is reached
    function timeout(sig senderSig) {
        require(checkSig(senderSig, sender));
        require(tx.time >= timeout);
    }
}

Tip: Read more about the CashScript language syntax in the Language Description.

Integrating into JavaScript

While more detailed examples are available on GitHub, we show an integration of the TransferWithTimeout contract in a JavaScript project.

After compiling the contract file to an artifact JSON with cashc, it can be imported into the CashScript SDK.

cashc ./transfer_with_timeout.cash --output ./transfer_with_timeout.json

const { ElectrumNetworkProvider, Contract, SignatureTemplate } = require('cashscript');
const { alice, bob, alicePk, bobPk } = require('./keys');

async function run() {
  // Import the TransferWithTimeout JSON artifact
  const artifact = require('./transfer_with_timeout.json');

  // Initialise a network provider for network operations
  const provider = new ElectrumNetworkProvider('mainnet');

  // Instantiate a new TransferWithTimeout contract
  const contract = new Contract(artifact, [alicePk, bobPk, 600000], provider);

  // Call the transfer function with Bob's signature
  // i.e. Bob claims the money that Alice has sent him
  const transferDetails = await contract.functions
    .transfer(new SignatureTemplate(bob))
    .to('bitcoincash:qrhea03074073ff3zv9whh0nggxc7k03ssh8jv9mkx', 10000)
    .send();
  console.log(transferDetails);

  // Call the timeout function with Alice's signature
  // i.e. Alice recovers the money that Bob has not claimed
  const timeoutDetails = await contract.functions
    .timeout(new SignatureTemplate(alice))
    .to('bitcoincash:qqeht8vnwag20yv8dvtcrd4ujx09fwxwsqqqw93w88', 10000)
    .send();
  console.log(timeoutDetails);
}

Tip: Read more about the JavaScript SDK in the SDK documentation.