Add code from express-unpkg repo

server/middleware/FileUtils.js

@@ -0,0 +1,35 @@
+const fs = require('fs')
+const mime = require('mime')
+
+const TextFiles = /\/?(LICENSE|README|CHANGES|AUTHORS|Makefile|\.[a-z]*rc|\.git[a-z]*|\.[a-z]*ignore)$/i
+
+const getContentType = (file) =>
+  TextFiles.test(file) ? 'text/plain' : mime.lookup(file)
+
+const getStats = (file) =>
+  new Promise((resolve, reject) => {
+    fs.lstat(file, (error, stats) => {
+      if (error) {
+        reject(error)
+      } else {
+        resolve(stats)
+      }
+    })
+  })
+
+const getFileType = (stats) => {
+  if (stats.isFile()) return 'file'
+  if (stats.isDirectory()) return 'directory'
+  if (stats.isBlockDevice()) return 'blockDevice'
+  if (stats.isCharacterDevice()) return 'characterDevice'
+  if (stats.isSymbolicLink()) return 'symlink'
+  if (stats.isSocket()) return 'socket'
+  if (stats.isFIFO()) return 'fifo'
+  return 'unknown'
+}
+
+module.exports = {
+  getContentType,
+  getStats,
+  getFileType
+}