Ethereum methods

Signing

You can request the user to sign a personal message like this:

// Type
type SignPersonal = (msgParams: {data: string|Uint8Array}, callback?: (error: any, data: string) => void) => void|Promise<string>;
 
// Usage
const signature = await tokenscript.personal.sign({data: "My message"});

This method is async but can also take a callback as well.

Note: If you need typed data signing, use the Ethereum Provider

getRpcUrls

The getRpcUrls method provides an array of RPC URLs for the specified chain ID:

// Type
type GetRpcUrls = (chain: number) => string[];
 
// Usage
const rpcUrls = tokenscript.eth.getRpcUrls(137);

These URLs are configured and provided by the TokenScript Engine.

getRpcProvider

Instead of requesting URLs and configuring the ethereum provider yourself, you can get an ethers.js provider directly:

// Type
type GetRpcProvider = (chain: number) => AbstractProvider; // ethers.AbstractProvider
 
// Usage
const provider = tokenscript.eth.getRpcProvider(137);

If more than one RPC URL is defined for the specified chain ethers.FallbackProvider is returned, otherwise ethers.JsonRpcProvider is returned.

getContractInfo

It's often helpful to get contract information based on the name specified in the TokenScript XML. In this way there is no need to hard-code contract addresses and ABI JSON within your Javascript code. Instead, this config information can be specified within the tokenscript-project.json environment variables and made available via this API method.

// Type
type GetContractInfo = (name: string, chain?: number) => {chain: number, address: string, abi: any};
 
// Usage
const contractInfo = tokenscript.eth.getContractInfo("MyReallyCoolToken");

If the chain parameter isn't provided, the chain of the current token is used or the first chain specified within ts:contract.

getContractInstance

Just like getContractInfo, we can get an ethers.Contract instance based on the name & chain provided. These contracts must have an ABI specified within ts:contract for the methods you want to execute.

// Type
type GetContractInstance = (name: string, chain?: number) => Contract; // ethers.Contract
 
// Usage
const contract = tokenscript.eth.getContractInstance("MyReallyCoolToken"); // ABI with getTokenPoints is defined in `ts:contract`
const points = await contract.getTokenPoints(token.tokenId);

This is most helpful when we want to read contract data within a card, without the use of TokenScript attributes that are loaded when the card is open.

Ethereum provider

To allow scenarios that are not supported by TokenScript's declarative transactions, the Card SDK provides an EIP-1193 proxy. This is the standard injected provider (window.ethereum) that you would be familiar with from integrating with Metamask and other browser extension wallets.

To use this provider, it's recommended that you wrap it with Ethers.js BrowserProvider like so:

const provider = new ethers.BrowserProvider(window.ethereum);
 
// You can then get an ethers contract instance to interact with a contract
const contract = new ethers.Contract(contractAddress, abi, provider);

Note: When using the injected provider, you must take care of chain switching, transaction notifications & error handling yourself.