subscribeToBalanceTopicTest.js

const blockchainProxy = require('blockchain-proxy-client')({apiServerAddress: 'http://localhost:3000'})
const tokenProxy = require('token-proxy-client')({apiServerAddress: 'http://localhost:5000'})

async function subscribeToBalanceTopic() {
  const [
    { contractAddress: tokenContractAddress },
    { prototype: availableBalanceTopic },
    { abi: tokenContractAbi },
  ] = await Promise.all([
    tokenProxy.contractAddress(),
    tokenProxy.getAvailableBalanceEventPrototype(),
    tokenProxy.getTokenContractABI(),
  ])

  console.log(availableBalanceTopic)
  const sseAvailableBalanceEvents = blockchainProxy.subscribeToBalanceTopicToContractEvents(
    tokenContractAddress,
    tokenContractAbi,
    JSON.stringify({
      fromBlock: 0,
      topics: [availableBalanceTopic]
    }),
    event => {
      const eventData = JSON.parse(event.data)
      console.log(eventData)
    }
  )
}

subscribeToBalanceTopic()