Covert CSV or TSV file to JSON file.

csv-to-json.js

/**
 * Standardize Task Data.
 * Service to be run in nodejs as an npm process (`npm run pre:serve`)
 * Drop into directory with CSV/TSV files to be parsed, and run as 
 * @example `node path/to/csv-to-json.js`
 */
const { once } = require('events')
const { createReadStream } = require('fs')
const { createInterface } = require('readline')
const { writeFile, readdir } = require('fs/promises')
const { basename } = require('path')

/**
 * Write the data to a JSON file.
 * @param {String} data
 * @param {String} fileName
 * @async
 */
const writeJSONfile = async (data, fileName = 'all.json') => {
  /**
   * Location to write file.
   * @type String
   * */
  const fileTarget = `${__dirname}/${fileName}`
  console.log(`Writing ${fileName} to ${fileTarget}`)

  try {
    /** @todo Enable this abort controller */
    // const controller = new AbortController();
    // const { signal } = controller;

    /** Define a writeFile process */
    const promise = writeFile(fileTarget,
      /** Formate JSON to have 2 space indentation. */
      JSON.stringify(data, null, 2)
    )

    // Abort the request before the promise settles.
    // controller.abort();

    await promise
  } catch (err) {
    // When a request is aborted - err is an AbortError
    console.error(err)
  }
}

/**
  * Reads directory with components and finds them (as `.vue` files.)
  * @async
  * @param targetDirectory Directory of where components can be found
  * @returns {Promise{Array}} List of Key:Value pairs of component names and locations
  */
const findBundleTargets = async (targetDirectory = `${__dirname}`) => {
  const filesPaths = []
  try {
    /**
      * Async read contents of directory
      * @see {@link https://nodejs.org/api/fs.html}
      */
    const files = await readdir(
      targetDirectory,
      {
        withFileTypes: true,
        encoding: 'utf8'
      }
    )
    /**
      * Iterate over found components.
      */
    for (const { name } of files) {
      /** Filter `.vue` only files. */
      if (name.endsWith('.csv')) {
        /** Transpile filename or a keyname */
        // const keyName = name.replace(/\.csv/g, '')
        /** Add filename and keyname to list */
        //  filesPaths.push({ [keyName]: `../${targetDirectory}/${name}` })

        filesPaths.push(`${targetDirectory}/${name}`)
      }
    }
  } catch (err) {
    /** Logs Errors cause this is a development service */
    console.error(err)
  }
  /** Return list of components for export */
  return filesPaths
}

/**
 * Process CSV or TSV file by line.
 * @param {String} filePath
 * @returns {Array<Object>} Collection to be stringified to JSON
 */
const processLineByLine = async (filePath) => {
  let lineCount = 0
  const compiledJson = []
  let keys

  try {
    const rl = createInterface({
      input: createReadStream(filePath),
      crlfDelay: Infinity
    })

    rl.on('line', (line) => {
      ++lineCount
      // Process the line.
      if (lineCount === 1) {
        // assign column names
        keys = line.split('\t') // split CSV or TSV by tab
      } else {
        // assign value to column for each row
        const data = line.split('\t')
        // in object format to be saved as JSON
        const entry = {}
        for (const index in data) {
          // match keyName,
          // assign value
          if (data[index] !== '') {
            entry[keys[index]] = data[index]
          }
        }
        // assigned `sourceFile`; file name is sourceFile value
        entry.sourceFile = basename(filePath, '.csv')
        compiledJson.push(entry)
      }
    })

    await once(rl, 'close')
    console.log('Data processed for:', filePath)
  } catch (err) {
    console.error(err)
  }
  return compiledJson
}

/** Define service implementation chain. */
const doBundle = async () => {
  const targetFiles = await findBundleTargets()

  const rendered = []
  for (const filePath of targetFiles) {
    rendered.push(await processLineByLine(filePath))
  }

  await writeJSONfile(
    rendered.flat(),
    'all-data.json'
  )
  console.log('--- Bundle Complete! ---')
}

/** [Self] Invoking function chain so calling the file runs the service. */
doBundle()