useCallSubscription

A React hook for calling a contract message on each new block and decoding a successful response or receiving an error. This is similar to useCall, except that there is no send() function in the response. The contract message will automatically be called on each new block. See useCall to learn about more shared features.

See useink/utils helpers for compatible functions that work well with this hook.

Usage​

import { useCallSubscription } from 'useink'
import { pickDecoded } from 'useink/utils'
import metadata from 'contract/metadata.json'

const CONTRACT_ADDRESS = '...'

// We define a response type so that `get.result.value.decoded` is of type SuccessfulResponse
interface SuccessfulResponse {
  foo: 'bar'
}

export const CallGetOnNewBlocks: React.FC = () => {
  const contract = useContract(CONTRACT_ADDRESS, metadata, 'aleph') 
  const args = ['arg-1', 2]
  const get = useCallSubscription<SuccessfulResponse>(contract, 'get', args)

  return (
    <>
      <h2>Get the Result the hard way: {get.result?.ok ? get.result.value.decoded.foo : '--'}</h2>
      <h2>Or the easy way: {pickDecoded(get.result)?.foo || '--'}</h2>
    </>
  )
}

Calling with a default caller address​

You must first define a default caller in configuration, then call the contract with options:

const args = ['blue pill'];
const callSub = useCallSubscription(contract, 'get', args, { defaultCaller: true });

Return Value​

{
  isSubmitting: boolean;
  result?: {
    ok: true;
    value: {
      raw: ContractExecResult; 
      decoded: T; // The response is decoded using contract Metadata, and of type `T`
    } | {
      ok: false;
      // error is set if a contract panics or has a failed assert(), or some other pallet errors.
      error: DispatchError | undefined; 
    }
  }
}