read and write file using yargs

Question

I have a .log file as input and I want to covert this log file to .json format and then write to an output file. For doing this operation I have used yargs package.

Here is the code I am trying:

import yargs from 'yargs'
import fs from 'fs'

// Check if the input file exist!
const checkFileExists = async(filepath: fs.PathLike) => {
  return new Promise((resolve, reject) => {
    fs.access(filepath, fs.constants.F_OK, (error) => {
      resolve(!error)
    })
  })
}

// Read and Write operation
const filterLogs = (inputPath: any, outputPath: any) => {
  // Read the input file
  // Make filterations
  // convert to json
  // create outfile if not EXIST!
  // write to outputfile
}

yargs
  .options({
    input: {
      alias: 'i',
      describe: 'input file path',
      demandOption: true,
      type: 'string',
    },
    output: {
      alias: 'o',
      describe: 'output file path',
      demandOption: true,
      type: 'string',
    },
  })
  .coerce('input', async function(arg) {
    return await checkFileExists(arg)
  })
  .help().argv

console.log(yargs.argv)

Running as:

tsc && node parser.js --input="./apps.log" --output=./error.json

How would I be able to run my functions to check if file exists then make other filterations and write to a output file?