useApi

Hook for accessing the Polkadot chain API client.

Import

import { useApi } from '@luno-kit/react'

Usage

Basic Usage

index.tsx

import { useApi } from '@luno-kit/react'

function App() {
  const { api, isApiReady, apiError } = useApi()

  if (apiError) {
    return <div>API Error: {apiError.message}</div>
  }

  if (!isApiReady) {
    return <div>Loading API...</div>
  }

  return <div>API is ready!</div>
}

config.ts

import { createConfig, kusama, polkadot, polkadotjsConnector } from '@luno-kit/react'

const config = createConfig({
  appName: 'luno with-vite example',
  chains: [polkadot, kusama],
  connectors: [polkadotjsConnector()],
  autoConnect: true,
});

Using API Methods

index.tsx

import { useApi } from '@luno-kit/react'

function BalanceChecker() {
  const { api, isApiReady } = useApi()

  const checkBalance = async (address: string) => {
    if (!api || !isApiReady) return

    try {
      // Query account balance
      const balance = await api.query.system.account(address)
      console.log('Balance:', balance.data.free.toString())
      
      // Get chain properties
      const properties = await api.rpc.system_properties()
      console.log('Chain properties:', properties)
      
      // Get current block
      const block = await api.rpc.chain_getBlock()
      console.log('Current block:', block.block.header.number)
    } catch (error) {
      console.error('API call failed:', error)
    }
  }

  return (
    <button 
      onClick={() => checkBalance('your-address-here')}
      disabled={!isApiReady}
    >
      Check Balance
    </button>
  )
}

config.ts

import { createConfig, kusama, polkadot, polkadotjsConnector } from '@luno-kit/react'

const config = createConfig({
  appName: 'luno with-vite example',
  chains: [polkadot, kusama],
  connectors: [polkadotjsConnector()],
  autoConnect: true,
});

Return Value

The hook returns an object with the following properties:

Property	Type	Description
api	LegacyClient | undefined	The Polkadot chain API client instance
isApiReady	boolean	Whether the API is ready for use
apiError	Error | null	Any error that occurred during API initialization

API Client Type

The api property is of type LegacyClient from the dedot library.

LegacyClient Interface

The LegacyClient provides high-level APIs for interacting with Substrate-based blockchains:

Query Methods

// Query account Balance
const balanceInfo = await api.query.system.account(address)

// Query balance locks
const balance = await api.query.balances.locks

RPC Methods

// Get chain information
const chain = await api.rpc.system.chain()
const properties = await api.rpc.system_properties()
const version = await api.rpc.system_version()

// Get block information
const block = await api.rpc.chain_getBlock()
const blockHash = await api.rpc.chain_getBlockHash(blockNumber)
const genesisHash = await api.rpc.chain_getBlockHash(0)

// Get metadata
const metadata = await api.rpc.state_getMetadata()

Transaction Methods

// Create transfer transaction
const transferTx = api.tx.balances.transferKeepAlive(address, amount)

Notes

• The API client is automatically initialized when a chain is selected
• Always check isApiReady before making API calls
• Handle apiError appropriately in your UI
• The LegacyClient provides both query methods and RPC methods
• For more advanced usage, refer to the dedot documentation