old_contents: var slashRe = new RegExp('/', 'g');
  var escapedSlashRe = new RegExp('~1', 'g');
  var tildeRe = /~/g;
  var escapedTildeRe = /~0/g;
  
  var Path = {
    escape: function (str) {
      if(!typeof(str) === 'string'){
        throw 'param str (' + str + ') is not a string';
      }
  
      return str.replace(tildeRe, '~0').replace(slashRe, '~1');
    },
  
    unescape: function (str) {
      if(typeof(str) == 'string') {
        return str.replace(escapedSlashRe, '/').replace(escapedTildeRe, '~');
      }
      else {
        return str;
      }
    }
  };
  
  module.exports = Path;
new_contents: 'use strict';
  
  var slashRe = new RegExp('/', 'g');
  var escapedSlashRe = new RegExp('~1', 'g');
  var tildeRe = /~/g;
  var escapedTildeRe = /~0/g;
  
  var Path = {
    escape: function (str) {
      if(!typeof(str) === 'string'){
        throw 'param str (' + str + ') is not a string';
      }
  
      return str.replace(tildeRe, '~0').replace(slashRe, '~1');
    },
  
    unescape: function (str) {
      if(typeof(str) == 'string') {
        return str.replace(escapedSlashRe, '/').replace(escapedTildeRe, '~');
      }
      else {
        return str;
      }
    }
  };
  
  module.exports = Path;
subject: fix missing use strict