script to sort json by given json file

sortjson.js

let fs = require('fs')

let config = {
  undefinedKeys: 'last', // 'alphabetical' or 'last'
  updateInPlace: true,
}

function main() {
  let command = process.argv[2]
  let filePath = process.argv[3]

  if (!filePath) {
    console.error('Please provide a file path as an argument.')
    process.exit(1)
  }
  
  if (command === 'learn') {
    fs.readFile(filePath, 'utf8', (err, data) => {
      if (err) {
        console.error('Error reading the file:', err)
        process.exit(1)
      }
    
      try {
        let jsonData = JSON.parse(data)
        let orderJSON = extractJSONOrder(jsonData)
        console.log(JSON.stringify(orderJSON, null, 2))
      } catch (parseErr) {
        console.error('Error parsing JSON:', parseErr)
        process.exit(1)
      }
    })
  } else if (command === 'apply') {
    let orderFilePath = process.argv[4]

    if (!orderFilePath) {
      console.error('Please provide a file path as an argument.')
      process.exit(1)
    }

    let inJSON = fs.readFileSync(filePath, 'utf8')
    let inData = JSON.parse(inJSON)
    let orderJSON = fs.readFileSync(orderFilePath, 'utf8')
    let orderData = JSON.parse(orderJSON)
    let orderedJSON = orderJSON2(inData, orderData)
    let res = JSON.stringify(orderedJSON, null, 2)
    if (config.updateInPlace) {
      fs.writeFileSync(filePath, res, 'utf8')
    } else {
      console.log(res)
    }
  }
}

function orderJSON2(inData, orderData) {
  if (Array.isArray(inData)) {
    for (let i=0; i<inData.length; i++) {
      inData[i] = orderJSON2(inData[i], orderData[0])
    }
    return inData //inData.map(orderJSON2)
  } else if (typeof inData === 'object') {
    let clonedObj = {}
    let inKeys = Object.keys(inData)
    let orderKeys = Object.keys(orderData)
    inKeys.sort((a, b) => {
      let aIndex = orderKeys.indexOf(a)
      let bIndex = orderKeys.indexOf(b)
      if (aIndex === -1 || bIndex === -1) {
        if (config.undefinedKeys === 'last') {
          return +1
        } else {
          return a.localeCompare(b)
        }
      }
      return orderKeys.indexOf(a) - orderKeys.indexOf(b)
    })

    for (let key of inKeys) {
      clonedObj[key] = orderJSON2(inData[key], orderData[key])
    }
    return clonedObj
  } else {
    return inData
  }
}

function extractJSONOrder(jsonData) {
  if (Array.isArray(jsonData)) {
    return jsonData.slice(0, 1).map(extractJSONOrder)
  } else if (typeof jsonData === 'object') {
    let clonedObj = {}
    for (let key in jsonData) {
      clonedObj[key] = extractJSONOrder(jsonData[key])
    }
    return clonedObj
  } else {
    return typeof jsonData
  }
}

main()