Take in JSON files, flatten then and output as CSV.

parseJsonDataToCSV.js

import fs from 'fs'

function reduceJsonToCSV (jsonData, prefix = '') {
  let parsedData = jsonData
  try {
    parsedData = JSON.parse(parsedData)
  } catch (e) {}

  const flatObj = Object.entries(parsedData).reduce((accum, [k, v]) => {
    const cellPrefix = prefix ? `${prefix}.${k}` : k
    if (Array.isArray(v)) {
      const reducedDataArray = reduceDataArray(v, cellPrefix)

      return { ...accum, ...reducedDataArray }
    }
    if (typeof v === 'object') {
      return { ...accum, ...reduceJsonToCSV(v, cellPrefix) }
    }
    return { ...accum, [cellPrefix]: v }
  }, {})

  return flatObj
}

function reduceDataArray (arr, prefix = '') {
  return Object.values(arr).reduce((accum, curr) => {
    return { ...accum, [`${prefix}.${curr.action_type}`]: curr.value }
  }, {})
}
function parseJsonToCSV (JSONData) {
  return Object.entries(reduceJsonToCSV(JSONData)).join('\n')
}

function getJsonFiles (dir) {
  const allFiles = fs.readdirSync(dir)
  return allFiles.filter(x => x.indexOf('.json') > -1)
}

function parseFilesToCSV (dir) {
  const JSONFiles = getJsonFiles(dir)
  JSONFiles.map(file => {
    const jsonData = fs.readFileSync(dir + file)
    const csvData = parseJsonToCSV(jsonData)
    fs.writeFileSync(dir + file.replace('.json', '.csv'), csvData)
  })
}

parseFilesToCSV('./data/')