This will create the output mapper for ethereum-to-graphql

genOutputFnMapper.js

const genOutputFn = (outputTypesDef) => {
  return (result) => {
    const resultsIsArr = Array.isArray(result)
    const outputTypesDefIsArray = Array.isArray(outputTypesDef)
    const combined = zipOutputWithResults(resultsIsArr, outputTypesDefIsArray, result, outputTypesDef)

    return combined.reduce((out, current) => {
      let { key, name, result } = current
      if (key === 'value') {
        if (Array.isArray(result)) {
          out[name] = result.map(item => {
            return parseValueResult(item)
          })
        } else {
          out[name] = parseValueResult(result)
        }
      } else if (key === 'bytes') {
        if (Array.isArray(result)) {
          out[name] = result.map(item => {
            return parseBytesResult(item)
          })
        } else {
          out[name] = parseBytesResult(result)
        }
      } else {
        out[name] = result
      }
      return out
    }, {})
  }
}

// Pupose of this method is to create the function that will receive data from Ethereum and return to graphQL for further processing
const genOutputFnMapper = ({ queryConverter }) => {
  return queryConverter
                .map(item => {
                  return { fnName: item.name, outputMapper: genOutputFn(item.types) }
                })
                .reduce((out, cur) => {
                  out[cur.fnName] = cur.outputMapper
                  return out
                }, {})
}