bitwig-nks-preview-generator/lib/gulp-nksf-filter.js

Streaming convert NKSF files to preview audio with using Bitwig Studio.

const fs = require('fs'),
      path = require('path'),
      plugin = require('./gulp-plugin-wrapper')

/**
 * default options
 * @type {Object}
 */
const defaultOptions = {
  skipExist: false // skip already exist preview
}

/**
 * options descriptions
 * @type {Object}
 */
const optionsDescriptions = {
  skipExist: 'skip .nksf file that already has preview audio'
}

/**
 * Gulp plugin for filter NKSF file.
 *
 * @function
 * @param {Object} options
 * @return {TransformStream} - through2.obj() object transform stream.
 */
const nksfFilter = (options) => {
  const opts = Object.assign({}, defaultOptions, options)
  return plugin('nksf-filter', _nksfFilter, opts)
}

function _nksfFilter(file, opts) {
  // does .nksf file has preview audio ?
  if (opts.skipExist) {
    const previewFile = path.join(file.dirname, '.previews', file.basename + '.ogg')
    const exists = fs.existsSync(previewFile)
    if (exists) {
      // reason for discard file.
      return 'already existing preview audio'
    }
  }
  // return message if want to discard file.
  return null
};

nksfFilter.defaultOptions = defaultOptions
nksfFilter.optionsDescriptions = optionsDescriptions
module.exports = nksfFilter