old_contents: 'use strict'
  const fs = require('fs')
  const path = require('path')
  
  exports.isSQLite = function isSQLite (sequelize) {
    return sequelize.options.dialect === 'sqlite'
  }
  
  exports.getImageMimeType = function getImageMimeType (imagePath) {
    var fileExtension = /[^.]+$/.exec(imagePath)
  
    switch (fileExtension[0]) {
      case 'bmp':
        return 'image/bmp'
      case 'gif':
        return 'image/gif'
      case 'jpg':
      case 'jpeg':
        return 'image/jpeg'
      case 'png':
        return 'image/png'
      case 'tiff':
        return 'image/tiff'
      default:
        return undefined
    }
  }
  
  exports.isRevealTheme = function isRevealTheme (theme) {
    if (fs.existsSync(path.join(__dirname, '..', 'public', 'build', 'reveal.js', 'css', 'theme', theme + '.css'))) {
      return theme
    }
    return undefined
  }
  
new_contents: 'use strict'
  const fs = require('fs')
  const path = require('path')
  
  exports.isSQLite = function isSQLite (sequelize) {
    return sequelize.options.dialect === 'sqlite'
  }
  
  exports.getImageMimeType = function getImageMimeType (imagePath) {
    const fileExtension = /[^.]+$/.exec(imagePath)
  
    switch (fileExtension[0]) {
      case 'bmp':
        return 'image/bmp'
      case 'gif':
        return 'image/gif'
      case 'jpg':
      case 'jpeg':
        return 'image/jpeg'
      case 'png':
        return 'image/png'
      case 'tiff':
        return 'image/tiff'
      default:
        return undefined
    }
  }
  
  exports.isRevealTheme = function isRevealTheme (theme) {
    if (fs.existsSync(path.join(__dirname, '..', 'public', 'build', 'reveal.js', 'css', 'theme', theme + '.css'))) {
      return theme
    }
    return undefined
  }
  
subject: fix lint on lib/utils.js