The Quais SDK is a complete Quai Network interaction library for JavaScript and TypeScript. Quais was built using the Ethers v6 framework, with significant changes made to support Quai Network’s multi-chain environment. This will be a very short introduction to the SDK’s features, installation, and important concepts.

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Quai Specific Features

API Compatibility

Quais utilizes the quai_ namespace, which allows developers to correctly make calls to any Quai RPC endpoint or wallet. Quai APIs also return different data types in comparison to Ethereum APIs, which the SDK is built to handle.

Utilities

The quais SDK has a number of additional utility functions designed to make handling the hierarchy much easier.

Contract Address Grinding

Similar to the address sharding mentioned above, contract addresses must have a shard prefix. During deployment, Quais handles address grinding to ensure the contract address has the correct shard prefix.
NOTE if the contract you are interacting with uses the CREATE2 opcode, quais is unable to handle the address grinding for you. You must ensure that when deploying a new contract using CREATE2 that the deployed contract will be in the proper address scope of the shard that you intend to deploy to. For more information and examples please refer to Sharding in the docs.

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Installation

To install Quais, simply install via NPM: 
npm install quais
To use the Quais SDK, you need to be running NodeJS with a version higher than 17.
All of the methods in Quais are exported at the root level and available through the quais object. Exports are also available for each module, which allows for more granular control of method imports. Quais supports imports in both Node.js and ESM in browser environments. 
// Import all methods
import { quais } from 'quais'

// Import specific methods
import { getZoneFromAddress, parseQuai } from 'quais'

// Import from a specific module
import { QuaiHDWallet } from 'quais/wallet'

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Concepts

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Provider

A Provider is the primary interface for reading data from any chain or ledger within Quai Network. With a Provider, you can query details about accounts, blocks and transactions, event logs, and much more. As the Provider class provides exclusively read-only access to the network, it is often paired alongside a Signer to create a read-and-write system for full interaction with the network. 
// Connect a provider to pelagus
const browserProvider = new quais.BrowserProvider(window.pelagus)

// Connect a provider to a remote node
const provider = new quais.JsonRpcProvider('https://rpc.quai.network', undefined, { usePathing: true })

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Transaction

Transactions are state changing operations made to any of the chains within the network. They are always accompanied by a fee, which covers the cost of transaction execution and information storage for network operators. Quais supports transactions on all shards across both the Quai and Qi ledgers. Account based Quai transactions are represented by the QuaiTransaction class. UTXO ledger Qi transactions are represented by the QiTransaction class. Transactions within Quai generally serve 4 different purposes: sending tokens from one user to another, deploying a smart contract, executing a state changing operation in a smart contract, or natively converting from Quai to Qi. 
// Create a transaction
const tx: QuaiTransactionRequest = {
	to: '0x1234567890123456789012345678901234567890',
	value: parseQuai('1.0'),
}

// Send a transaction
await signer.sendTransaction(tx)

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Contract

A Contract is a piece of code that has been deployed to and stored on the Quai ledger virtual machine. They do not exist on the Qi ledger. Contract state changing operations can be executed using a Signer and data can be from them using a Provider. 
// create a contract
const contract = new quais.Contract(contractAddress, contractABI, provider)

// call a read-only contract function
const symbol = await contract.symbol()