diff --git a/demo/nodejs/index.js b/demo/nodejs/index.js
index 1d65ae5d7..602db7323 100644
--- a/demo/nodejs/index.js
+++ b/demo/nodejs/index.js
@@ -1,10 +1,12 @@
 const Liquid = require('../..')
 
-let engine = new Liquid()
-let src = 'Welcome to {{ name | capitalize}}, access time: {{date|date: "%H:%M:%S"}}'
+let engine = new Liquid({
+  root: __dirname,
+  extname: '.liquid'
+})
 let ctx = {
-  name: 'Liquid',
-  date: new Date()
+  todos: ['fork and clone', 'make it better', 'make a pull request'],
+  title: 'Welcome to liquidjs!'
 }
 
-engine.parseAndRender(src, ctx).then(console.log)
+engine.renderFile('todolist', ctx).then(console.log)
diff --git a/demo/nodejs/todolist.liquid b/demo/nodejs/todolist.liquid
new file mode 100644
index 000000000..77c3edb64
--- /dev/null
+++ b/demo/nodejs/todolist.liquid
@@ -0,0 +1,5 @@
+<ul>
+  {% for todo in todos %}
+  <li>{{forloop.index}} - {{todo}}</li>
+  {% endfor %}
+</ul>
diff --git a/package.json b/package.json
index 0b31c76d7..7d2f8d116 100644
--- a/package.json
+++ b/package.json
@@ -10,14 +10,14 @@
     "coveralls": "nyc report --reporter=text-lcov --require babel-core/register mocha test/ --recursive | coveralls",
     "dist": "npm run babelify && npm run browserify && npm run uglify",
     "babelify": "babel src -d build",
-    "browserify": "browserify build/index.js -s Liquid --ignore path --global true > dist/liquid.js",
-    "uglify": "uglifyjs dist/liquid.js --compress warnings=false --mangle --output dist/liquid.min.js",
-    "demo:browser": "echo open http://localhost:8080/demo/browser && http-server",
+    "browserify": "browserify src/index.js -s Liquid --ignore path -t [ babelify --presets [ es2015 ] ] > dist/liquid.js",
+    "uglify": "uglifyjs dist/liquid.js --compress warnings=false --mangle toplevel --output dist/liquid.min.js",
+    "demo:browser": "echo open http://localhost:8080/demo/browser && http-server -c-1",
     "demo:nodejs": "node ./demo/nodejs/index.js",
     "demo:express": "cd ./demo/express/ && npm start",
     "preversion": "npm run lint && npm test",
     "version": "npm run dist && git add -A dist",
-    "postversion": "git push && git push --tags"
+    "postversion": "git push --tags"
   },
   "repository": {
     "type": "git",
diff --git a/src/index.js b/src/index.js
index a6faa49f0..7304a2350 100644
--- a/src/index.js
+++ b/src/index.js
@@ -14,7 +14,7 @@ import {isTruthy, isFalsy, evalExp, evalValue} from './syntax.js'
 import tags from './tags'
 import filters from './filters'
 import {anySeries} from './util/promise.js'
-import Errors from './util/error.js'
+import {ParseError, TokenizationEroor, RenderBreakError, AssertionError} from './util/error.js'
 
 let _engine = {
   init: function (tag, filter, options) {
@@ -174,10 +174,10 @@ function normalizeStringArray (value) {
 }
 
 const Types = {
-  ParseError: Errors.ParseError,
-  TokenizationEroor: Errors.TokenizationError,
-  RenderBreakError: Errors.RenderBreakError,
-  AssertionError: Errors.AssertionError
+  ParseError,
+  TokenizationEroor,
+  RenderBreakError,
+  AssertionError
 }
 
 factory.isTruthy = isTruthy
diff --git a/src/tags/increment.js b/src/tags/increment.js
index bc881635b..7437470d4 100644
--- a/src/tags/increment.js
+++ b/src/tags/increment.js
@@ -1,5 +1,4 @@
-'use strict'
-const Liquid = require('..')
+const Liquid = require('../index')
 const assert = require('../util/assert.js')
 const lexical = Liquid.lexical
 const types = require('../scope').types
diff --git a/src/util/error.js b/src/util/error.js
index f444b0b98..407cf2995 100644
--- a/src/util/error.js
+++ b/src/util/error.js
@@ -21,13 +21,13 @@ function initLiquidError (err, token) {
       (err.stack ? '\nFrom ' + err.stack : '')
 }
 
-function TokenizationError (message, token) {
+export function TokenizationError (message, token) {
   initLiquidError.call(this, {message: message}, token)
 }
 TokenizationError.prototype = Object.create(Error.prototype)
 TokenizationError.prototype.constructor = TokenizationError
 
-function ParseError (e, token) {
+export function ParseError (e, token) {
   _.assign(this, e)
   this.originalError = e
 
@@ -36,7 +36,7 @@ function ParseError (e, token) {
 ParseError.prototype = Object.create(Error.prototype)
 ParseError.prototype.constructor = ParseError
 
-function RenderError (e, tpl) {
+export function RenderError (e, tpl) {
   // return the original render error
   if (e instanceof RenderError) {
     return e
@@ -49,14 +49,14 @@ function RenderError (e, tpl) {
 RenderError.prototype = Object.create(Error.prototype)
 RenderError.prototype.constructor = RenderError
 
-function RenderBreakError (message) {
+export function RenderBreakError (message) {
   initError.call(this)
   this.message = message + ''
 }
 RenderBreakError.prototype = Object.create(Error.prototype)
 RenderBreakError.prototype.constructor = RenderBreakError
 
-function AssertionError (message) {
+export function AssertionError (message) {
   initError.call(this)
   this.message = message + ''
 }
@@ -98,11 +98,3 @@ function mkMessage (msg, token) {
   }
   return msg
 }
-
-module.exports = {
-  TokenizationError,
-  ParseError,
-  RenderBreakError,
-  AssertionError,
-  RenderError
-}
diff --git a/test/options/strict.js b/test/options/strict.js
index 7583ea5fd..f699da17f 100644
--- a/test/options/strict.js
+++ b/test/options/strict.js
@@ -1,6 +1,7 @@
-const chai = require('chai')
+import Liquid from '../../src'
+import chai from 'chai'
+
 const expect = chai.expect
-const Liquid = require('../../src')
 chai.use(require('chai-as-promised'))
 
 describe('strict options', function () {
diff --git a/test/tags/capture.js b/test/tags/capture.js
index 19e3eb698..0d38faed0 100644
--- a/test/tags/capture.js
+++ b/test/tags/capture.js
@@ -1,6 +1,6 @@
-'use strict'
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src/index'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/case.js b/test/tags/case.js
index ef987a2ea..97f87a40f 100644
--- a/test/tags/case.js
+++ b/test/tags/case.js
@@ -1,5 +1,6 @@
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/comment.js b/test/tags/comment.js
index b428ccf99..5c930da2e 100644
--- a/test/tags/comment.js
+++ b/test/tags/comment.js
@@ -1,5 +1,6 @@
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/cycle.js b/test/tags/cycle.js
index ab2396f39..5d4a2edd3 100644
--- a/test/tags/cycle.js
+++ b/test/tags/cycle.js
@@ -1,5 +1,6 @@
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/decrement.js b/test/tags/decrement.js
index e7c0ac4d3..85cbeab9f 100644
--- a/test/tags/decrement.js
+++ b/test/tags/decrement.js
@@ -1,6 +1,6 @@
-'use strict'
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/for.js b/test/tags/for.js
index 682598d47..d9885d5b3 100644
--- a/test/tags/for.js
+++ b/test/tags/for.js
@@ -1,5 +1,6 @@
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/if.js b/test/tags/if.js
index be3dc8106..8fc417c48 100644
--- a/test/tags/if.js
+++ b/test/tags/if.js
@@ -1,5 +1,6 @@
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src/index'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/include.js b/test/tags/include.js
index 0327d26fd..2b3599e57 100644
--- a/test/tags/include.js
+++ b/test/tags/include.js
@@ -1,6 +1,7 @@
-const Liquid = require('../..')
-const mock = require('mock-fs')
-const chai = require('chai')
+import Liquid from '../../src'
+import mock from 'mock-fs'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/increment.js b/test/tags/increment.js
index 6dafef3d7..a29adb48b 100644
--- a/test/tags/increment.js
+++ b/test/tags/increment.js
@@ -1,6 +1,6 @@
-'use strict'
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/layout.js b/test/tags/layout.js
index 7c98d04f9..244a5807c 100644
--- a/test/tags/layout.js
+++ b/test/tags/layout.js
@@ -1,6 +1,7 @@
-const Liquid = require('../..')
-const mock = require('mock-fs')
-const chai = require('chai')
+import Liquid from '../../src'
+import mock from 'mock-fs'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/raw.js b/test/tags/raw.js
index a367d57c7..ab6c45b8c 100644
--- a/test/tags/raw.js
+++ b/test/tags/raw.js
@@ -1,5 +1,6 @@
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/tablerow.js b/test/tags/tablerow.js
index 8c6c413a6..fa585541e 100644
--- a/test/tags/tablerow.js
+++ b/test/tags/tablerow.js
@@ -1,5 +1,6 @@
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/tags/unless.js b/test/tags/unless.js
index 5c7d6c437..275247abf 100644
--- a/test/tags/unless.js
+++ b/test/tags/unless.js
@@ -1,5 +1,6 @@
-const Liquid = require('../..')
-const chai = require('chai')
+import Liquid from '../../src'
+import chai from 'chai'
+
 const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
diff --git a/test/util/error.js b/test/util/error.js
index bfcf5f50d..9c1bc750c 100644
--- a/test/util/error.js
+++ b/test/util/error.js
@@ -1,11 +1,13 @@
-const chai = require('chai')
+import Liquid from '../../src'
+import mock from 'mock-fs'
+import chai from 'chai'
+import path from 'path'
+
 const expect = chai.expect
-const mock = require('mock-fs')
-const path = require('path')
 chai.use(require('chai-as-promised'))
 
-let engine = require('../..')()
-let strictEngine = require('../..')({
+let engine = Liquid()
+let strictEngine = Liquid({
   strict_variables: true,
   strict_filters: true
 })
@@ -95,7 +97,7 @@ describe('error', function () {
 
   describe('RenderError', function () {
     beforeEach(function () {
-      engine = require('../..')({
+      engine = Liquid({
         root: '/'
       })
       engine.registerTag('throwingTag', {
@@ -269,7 +271,7 @@ describe('error', function () {
 
   describe('ParseError', function () {
     beforeEach(function () {
-      engine = require('../..')()
+      engine = Liquid()
       engine.registerTag('throwsOnParse', {
         parse: function () {
           throw new Error('intended parse error')
diff --git a/test/util/underscore.js b/test/util/underscore.js
index 7b9c1bf7a..2dfb5c8cf 100644
--- a/test/util/underscore.js
+++ b/test/util/underscore.js
@@ -1,6 +1,6 @@
 import chai from 'chai'
 import sinon from 'sinon'
-import Errors from '../../src/util/error.js'
+import {RenderError, RenderBreakError} from '../../src/util/error.js'
 import _ from '../../src/util/underscore.js'
 
 const expect = chai.expect
@@ -17,10 +17,10 @@ describe('util/underscore', function () {
           input: 'xx'
         }
       }
-      expect(_.isError(new Errors.RenderError(new Error(), tpl))).to.be.true
+      expect(_.isError(new RenderError(new Error(), tpl))).to.be.true
     })
     it('should return true for RenderBreakError', function () {
-      expect(_.isError(new Errors.RenderBreakError())).to.be.true
+      expect(_.isError(new RenderBreakError())).to.be.true
     })
   })
   describe('.isString()', function () {
diff --git a/test/util/url.js b/test/util/url.js
index ec6ded851..4622bfac7 100644
--- a/test/util/url.js
+++ b/test/util/url.js
@@ -1,6 +1,7 @@
-const chai = require('chai')
+import {resolve} from '../../src/util/url.js'
+import chai from 'chai'
+
 const expect = chai.expect
-const url = require('../../src/util/url.js')
 
 describe('util/url', function () {
   if (process.version.match(/^v(\d+)/)[1] < 8) {
@@ -22,41 +23,41 @@ describe('util/url', function () {
   describe('resolve', function () {
     describe('root', function () {
       it('should support width relative path', function () {
-        expect(url.resolve('./views', 'foo'))
+        expect(resolve('./views', 'foo'))
           .to.equal('https://example.com/foo/bar/views/foo')
-        expect(url.resolve('./views/', 'foo'))
+        expect(resolve('./views/', 'foo'))
           .to.equal('https://example.com/foo/bar/views/foo')
       })
       it('should support width absolute path', function () {
-        expect(url.resolve('/views', 'foo'))
+        expect(resolve('/views', 'foo'))
           .to.equal('https://example.com/views/foo')
-        expect(url.resolve('/views/', 'foo'))
+        expect(resolve('/views/', 'foo'))
           .to.equal('https://example.com/views/foo')
       })
       it('should support with empty', function () {
-        expect(url.resolve('', 'page.html'))
+        expect(resolve('', 'page.html'))
           .to.equal('https://example.com/foo/bar/page.html')
       })
       it('should support with url', function () {
-        expect(url.resolve('https://example.com/views', 'page.html'))
+        expect(resolve('https://example.com/views', 'page.html'))
           .to.equal('https://example.com/views/page.html')
-        expect(url.resolve('https://example.com/views/', 'page.html'))
+        expect(resolve('https://example.com/views/', 'page.html'))
           .to.equal('https://example.com/views/page.html')
       })
       it('should get the first value when argument is array', function () {
-        expect(url.resolve(['https://example.com/views', 'https://google.com/views'], 'page.html'))
+        expect(resolve(['https://example.com/views', 'https://google.com/views'], 'page.html'))
           .to.equal('https://example.com/views/page.html')
-        expect(url.resolve(['https://example.com/views/', 'https://google.com/views'], 'page.html'))
+        expect(resolve(['https://example.com/views/', 'https://google.com/views'], 'page.html'))
           .to.equal('https://example.com/views/page.html')
       })
     })
     describe('path', function () {
       it('should support width relative path', function () {
-        expect(url.resolve('./views/', 'page.html'))
+        expect(resolve('./views/', 'page.html'))
           .to.equal('https://example.com/foo/bar/views/page.html')
       })
       it('should support with absolute path', function () {
-        expect(url.resolve('/views/', '/page.html'))
+        expect(resolve('/views/', '/page.html'))
           .to.equal('https://example.com/page.html')
       })
     })
diff --git a/test/whitespace-control.js b/test/whitespace-control.js
index 69d440da9..a0856c24e 100644
--- a/test/whitespace-control.js
+++ b/test/whitespace-control.js
@@ -1,7 +1,8 @@
-const chai = require('chai')
-const expect = chai.expect
-const Liquid = require('..')
+import chai from 'chai'
+import Liquid from '../src'
+
 const liquid = new Liquid()
+const expect = chai.expect
 chai.use(require('chai-as-promised'))
 
 const cases = [
diff --git a/test/xhr.js b/test/xhr.js
index 01e224966..9a35f76bc 100644
--- a/test/xhr.js
+++ b/test/xhr.js
@@ -1,4 +1,4 @@
-import Liquid from '..'
+import Liquid from '../src'
 import sinon from 'sinon'
 import chai from 'chai'
 const expect = chai.expect