PouchDB relative dir fail

gistfile1.js

// PouchDB relative dir failure gist
// in some dir containing this .js file, mkdir db
// Run 'node THIS-GIST.js' :: success!
// change one dir up. run 'node childdir/THIS-GIST.js' :: fail :(

var PouchDB = require('pouchdb');

var dbRoot = './db/',
    dbTest = new PouchDB(dbRoot + 'pouchdbDirTest'),
    now = (new Date()).getTime().toString();

dbTest.put({time: now}, now)
  .then(function putS(r){
    console.log('Success!');
    console.dir(r);
  })
  .catch(function putF(e){
    console.log('Fail!', e.stack);
  });