core: Upgrade from babel5 -> babel6

.babelrc

@@ -1,7 +1,4 @@
-/*{
-  "presets": ["es2015"]
-}*/
-
 {
-  "stage": 0
+  "presets": ["es2015"],
+  "plugins": ["transform-object-assign"]
 }

CHANGELOG.md

@@ -57,6 +57,7 @@ Ideas that will be planned and find their way into a release at one point
 - [ ] google: Make sure http://server.uppy.io is targeted in; and localhost is targeted elsewhere (@kvz)
 - [ ] test: Setup one modal/dragdrop acceptance test (@arturi)
 - [ ] test: Make failing acceptance tests fatal (@kvz)
+- [x] core: Upgrade from babel5 -> babel6 (@kvz)
 - [x] test: Add a passing dummy i18n acceptance test, move failing multipart test to `v0.5.0` dir (@kvz)
 - [x] test: Get Firefox acceptance tests up and running both local and on Travis CI. Currently both failing on `StaleElementReferenceError: Element not found in the cache - perhaps the page has changed since it was looked up` https://travis-ci.org/transloadit/uppy/builds/121175389#L478
 - [x] test: Write one actual test (e.g. Multipart) (#2, #23, @hedgerh)

package.json

@@ -51,14 +51,18 @@
   },
   "homepage": "https://github.com/transloadit/uppy#readme",
   "devDependencies": {
-    "babel": "5.8.34",
-    "babel-eslint": "4.1.5",
-    "babelify": "6.4.0",
+    "babel-core": "6.7.4",
+    "babel-loader": "6.2.4",
+    "babel-preset-es2015": "^6.0.0",
+    "babel-polyfill": "6.7.4",
+    "babel-eslint": "6.0.2",
+    "babel-plugin-transform-object-assign": "6.5.0",
+    "babelify": "7.2.0",
     "browser-sync": "2.10.0",
     "browserify": "12.0.1",
     "chalk": "1.1.1",
     "disc": "1.3.2",
-    "eslint": "2.4.0",
+    "eslint": "2.7.0",
     "eslint-config-standard": "5.1.0",
     "eslint-plugin-promise": "1.1.0",
     "eslint-plugin-standard": "1.3.2",
@@ -74,6 +78,8 @@
     "watchify": "3.6.1"
   },
   "dependencies": {
+    "babel-preset-stage-0": "6.5.0",
+    "babel-register": "6.7.2",
     "drag-drop": "2.11.0",
     "tus-js-client": "1.1.3",
     "yo-yo": "1.1.1"

test/acceptance/index.js

@@ -1,5 +1,2 @@
-require('babel/register')({
-  stage: 0
-})
-
+require('babel-register')
 require('./i18n.spec.js')

test/unit/core.spec.js

@@ -1,27 +1,27 @@
-var test = require('tape')
-var Uppy = require('../../src/core/Core.js')
+import test from 'tape'
+import Core from '../../src/core/Core.js'
+import Acquirer1Plugin from './mocks/plugin-acquirer1.js'
+import Acquirer2Plugin from './mocks/plugin-acquirer2.js'
 
 test('core', function (t) {
-  const uppy = new Uppy()
+  const uppy = new Core()
 
   t.equal(typeof uppy, 'object', '`new Core()` should return an `object`')
-  t.ok(uppy instanceof Uppy, '`uppy` should be an instance of `Uppy` core')
+  t.ok(uppy instanceof Core, '`uppy` should be an instance of `Core` core')
   t.end()
 })
 
 test('use plugins', function (t) {
-  const AcquirerPlugin = require('./mocks/plugin-acquirer1.js')
-  const uppy = new Uppy()
+  const uppy = new Core()
   uppy
-    .use(AcquirerPlugin)
+    .use(Acquirer1Plugin)
 
   t.equal(Object.keys(uppy.plugins).length, 1, 'should add a plugin to the plugins stack')
   t.end()
 })
 
 test('noDuplicates', function (t) {
-  const Acquirer1Plugin = require('./mocks/plugin-acquirer1.js')
-  const uppyTwoAcquirers = new Uppy()
+  const uppyTwoAcquirers = new Core()
 
   uppyTwoAcquirers.use(Acquirer1Plugin)
   const fn = uppyTwoAcquirers.use.bind(uppyTwoAcquirers, Acquirer1Plugin)
@@ -31,15 +31,12 @@ test('noDuplicates', function (t) {
 })
 
 test('autoProceed', function (t) {
-  const Acquirer1Plugin = require('./mocks/plugin-acquirer1.js')
-  const Acquirer2Plugin = require('./mocks/plugin-acquirer2.js')
-
-  const uppyOneAcquirer = new Uppy()
+  const uppyOneAcquirer = new Core()
   uppyOneAcquirer
     .use(Acquirer1Plugin)
     .run()
 
-  const uppyTwoAcquirers = new Uppy()
+  const uppyTwoAcquirers = new Core()
   uppyTwoAcquirers
     .use(Acquirer1Plugin)
     .use(Acquirer2Plugin)

test/unit/index.js

@@ -1,6 +1,3 @@
-require('babel/register')({
-  stage: 0
-})
-
+require('babel-register')
 require('./core.spec.js')
 require('./translator.spec.js')

test/unit/mocks/plugin-acquirer1.js

@@ -1,4 +1,4 @@
-const Plugin = require('../../../src/plugins/Plugin.js')
+import Plugin from '../../../src/plugins/Plugin.js'
 
 export default class TestSelector1 extends Plugin {
   constructor (core, opts) {

test/unit/mocks/plugin-acquirer2.js

@@ -1,4 +1,4 @@
-const Plugin = require('../../../src/plugins/Plugin.js')
+import Plugin from '../../../src/plugins/Plugin.js'
 
 export default class TestSelector2 extends Plugin {
   constructor (core, opts) {

test/unit/translator.spec.js

@@ -1,8 +1,9 @@
-var test = require('tape')
-var Core = require('../../src/core/index.js')
+import test from 'tape'
+import Core from '../../src/core/index.js'
+import russian from '../../src/locales/ru_RU.js'
+import english from '../../src/locales/en_US.js'
 
 test('translation', function (t) {
-  const russian = require('../../src/locales/ru_RU.js')
   const core = new Core({locales: russian})
 
   t.equal(
@@ -15,7 +16,6 @@ test('translation', function (t) {
 })
 
 test('interpolation', function (t) {
-  const english = require('../../src/locales/en_US.js')
   const core = new Core({locales: english})
 
   t.equal(
@@ -28,7 +28,6 @@ test('interpolation', function (t) {
 })
 
 test('pluralization', function (t) {
-  const russian = require('../../src/locales/ru_RU.js')
   const core = new Core({locales: russian})
 
   t.equal(