efx-api-node/src/api/account/token_balance.js

<img src="https://avatars3.githubusercontent.com/u/33315316?s=200&v=4" align="right" />

module.exports = (efx, token) => {
  const currency = efx.config['0x'].tokenRegistry[token]
  const action = 'balanceOf'
  const args = [ efx.get('account') ]

  return efx.eth.call(efx.contract.abi.token, currency.wrapperAddress, action, args)
}