helper.js

const fs = require('fs')
const path = require('path')

function generateFilenames (directory, filenames) {
  return filenames.reduce((acc, filename) => {
    if (filename.indexOf('*') < 0) {
      acc.push(filename)
      return acc
    } else if (!fs.existsSync(directory)) {
      return acc
    }
    // We use a UNIX synthax in our classifier, so we need to transform this in to a JS RegExp
    const regex = new RegExp(filename.replace('*', '.*'))

    return acc.concat(fs.readdirSync(directory).filter(f => regex.test(f)))
  }, [])
}

function singleResourceLoader (filepath, add, remove) {
  if (!fs.existsSync(filepath)) { return }
  let dict = fs.readFileSync(filepath, 'utf8')
  dict.split('\n').forEach(row => {
    if (row.trim().startsWith('#')) {
      // Do nothing, this is a comment
    } else if (row.startsWith('!')) {
      row.substring(1).split('|').forEach(remove)
    } else {
      row.split('|').forEach(add)
    }
  })
}

function multiResourceLoader ({ directory, filenames }, add, remove) {
  generateFilenames(directory, filenames).forEach(filename => {
    let filepath = path.join(directory, filename)
    singleResourceLoader(filepath, add, remove)
  })
}

function resourceLoader (dictPath) {
  return (opts, add, remove) => {
    if (typeof opts === 'string') {
      let filename = path.join(dictPath, opts)
      return singleResourceLoader(filename, add, remove)
    }
    let directory = path.join(dictPath, opts.directory)
    multiResourceLoader({ directory: directory, filenames: opts.filenames }, add, remove)
  }
}

module.exports.generateFilenames = generateFilenames
module.exports.resourceLoader = resourceLoader