chore(project): es6ify

* use import / export
* TOOLKIT: export individual functions from utlitites
* TEST: localize TestHelper includes

BREAKING CHANGE:

* utilities expose individual functions now
* libraries built upon diagram-js must now use a ES6
  transpiler to consume modules and resolve import/export
  declarations
* without special precautions using from CommonJS libraries
  requires loading the `default` export in most cases via
  `require('diagram-js/some-component').default`

lib/Diagram.js

@@ -1,6 +1,8 @@
 'use strict';
 
-var Injector = require('didi').Injector;
+import { Injector } from 'didi';
+
+import CoreModule from './core';
 
 
 /**
@@ -77,9 +79,7 @@ function createInjector(options) {
     'config': ['value', options]
   };
 
-  var coreModule = require('./core');
-
-  var modules = [ configModule, coreModule ].concat(options.modules || []);
+  var modules = [ configModule, CoreModule ].concat(options.modules || []);
 
   return bootstrap(modules);
 }
@@ -107,15 +107,21 @@ function createInjector(options) {
  * }
  *
  * // export as module
- * module.exports = {
+ * export default {
  *   __init__: [ 'myLoggingPlugin' ],
  *     myLoggingPlugin: [ 'type', MyLoggingPlugin ]
  * };
  *
  *
  * // instantiate the diagram with the new plug-in
  *
- * var diagram = new Diagram({ modules: [ require('path-to-my-logging-plugin') ] });
+ * import MyLoggingModule from 'path-to-my-logging-plugin';
+ *
+ * var diagram = new Diagram({
+ *   modules: [
+ *     MyLoggingModule
+ *   ]
+ * });
  *
  * diagram.invoke([ 'canvas', function(canvas) {
  *   // add shape to drawing canvas
@@ -128,7 +134,7 @@ function createInjector(options) {
  * @param {Array<didi.Module>} [options.modules] external modules to instantiate with the diagram
  * @param {didi.Injector} [injector] an (optional) injector to bootstrap the diagram with
  */
-function Diagram(options, injector) {
+export default function Diagram(options, injector) {
 
   // create injector unless explicitly specified
   this.injector = injector = injector || createInjector(options);
@@ -180,8 +186,6 @@ function Diagram(options, injector) {
   this.get('eventBus').fire('diagram.init');
 }
 
-module.exports = Diagram;
-
 
 /**
  * Destroys the diagram

lib/command/CommandHandler.js

@@ -4,9 +4,7 @@
  * A command handler that may be registered with the
  * {@link CommandStack} via {@link CommandStack#registerHandler}.
  */
-function CommandHandler() {}
-
-module.exports = CommandHandler;
+export default function CommandHandler() {}
 
 
 /**

lib/command/CommandInterceptor.js

@@ -1,18 +1,16 @@
 'use strict';
 
-var forEach = require('min-dash').forEach,
-    isFunction = require('min-dash').isFunction,
-    isArray = require('min-dash').isArray,
-    isNumber = require('min-dash').isNumber;
+import {
+  forEach,
+  isFunction,
+  isArray,
+  isNumber,
+  isObject
+} from 'min-dash';
 
 
 var DEFAULT_PRIORITY = 1000;
 
-
-function isObject(element) {
-  return typeof element === 'object';
-}
-
 /**
  * A utility that can be used to plug-in into the command execution for
  * extension and/or validation.
@@ -21,9 +19,9 @@ function isObject(element) {
  *
  * @example
  *
- * var inherits = require('inherits');
+ * import inherits from 'inherits';
  *
- * var CommandInterceptor = require('diagram-js/lib/command/CommandInterceptor');
+ * import CommandInterceptor from 'diagram-js/lib/command/CommandInterceptor';
  *
  * function CommandLogger(eventBus) {
  *   CommandInterceptor.call(this, eventBus);
@@ -36,14 +34,12 @@ function isObject(element) {
  * inherits(CommandLogger, CommandInterceptor);
  *
  */
-function CommandInterceptor(eventBus) {
+export default function CommandInterceptor(eventBus) {
   this._eventBus = eventBus;
 }
 
 CommandInterceptor.$inject = [ 'eventBus' ];
 
-module.exports = CommandInterceptor;
-
 function unwrapEvent(fn, that) {
   return function(event) {
     return fn.call(that || null, event.context, event.command, event);

lib/command/CommandStack.js

@@ -1,7 +1,9 @@
 'use strict';
 
-var uniqueBy = require('min-dash').uniqueBy,
-    isArray = require('min-dash').isArray;
+import {
+  uniqueBy,
+  isArray
+} from 'min-dash';
 
 
 /**
@@ -80,7 +82,7 @@ var uniqueBy = require('min-dash').uniqueBy,
  * @param {EventBus} eventBus
  * @param {Injector} injector
  */
-function CommandStack(eventBus, injector) {
+export default function CommandStack(eventBus, injector) {
 
   /**
    * A map of all registered command handlers.
@@ -129,8 +131,6 @@ function CommandStack(eventBus, injector) {
 
 CommandStack.$inject = [ 'eventBus', 'injector' ];
 
-module.exports = CommandStack;
-
 
 /**
  * Execute a command

lib/command/index.js

@@ -1,3 +1,5 @@
-module.exports = {
-  commandStack: [ 'type', require('./CommandStack') ]
+import CommandStack from './CommandStack';
+
+export default {
+  commandStack: [ 'type', CommandStack ]
 };

lib/core/Canvas.js

@@ -1,23 +1,33 @@
 'use strict';
 
-var isNumber = require('min-dash').isNumber,
-    assign = require('min-dash').assign,
-    forEach = require('min-dash').forEach,
-    every = require('min-dash').every,
-    debounce = require('min-dash').debounce,
-    bind = require('min-dash').bind,
-    reduce = require('min-dash').reduce;
-
-var Collections = require('../util/Collections'),
-    Elements = require('../util/Elements');
-
-var svgAppend = require('tiny-svg').append,
-    svgAttr = require('tiny-svg').attr,
-    svgClasses = require('tiny-svg').classes,
-    svgCreate = require('tiny-svg').create,
-    svgTransform = require('tiny-svg').transform;
-
-var createMatrix = require('tiny-svg').createMatrix;
+import {
+  isNumber,
+  assign,
+  forEach,
+  every,
+  debounce,
+  bind,
+  reduce
+} from 'min-dash';
+
+import {
+  add as collectionAdd,
+  remove as collectionRemove
+} from '../util/Collections';
+
+import {
+  getType
+} from '../util/Elements';
+
+import {
+  append as svgAppend,
+  attr as svgAttr,
+  classes as svgClasses,
+  create as svgCreate,
+  transform as svgTransform
+} from 'tiny-svg';
+
+import { createMatrix as createMatrix } from 'tiny-svg';
 
 
 function round(number, resolution) {
@@ -91,7 +101,7 @@ var REQUIRED_MODEL_ATTRS = {
  * @param {GraphicsFactory} graphicsFactory
  * @param {ElementRegistry} elementRegistry
  */
-function Canvas(config, eventBus, graphicsFactory, elementRegistry) {
+export default function Canvas(config, eventBus, graphicsFactory, elementRegistry) {
 
   this._eventBus = eventBus;
   this._elementRegistry = elementRegistry;
@@ -100,9 +110,12 @@ function Canvas(config, eventBus, graphicsFactory, elementRegistry) {
   this._init(config || {});
 }
 
-Canvas.$inject = [ 'config.canvas', 'eventBus', 'graphicsFactory', 'elementRegistry' ];
-
-module.exports = Canvas;
+Canvas.$inject = [
+  'config.canvas',
+  'eventBus',
+  'graphicsFactory',
+  'elementRegistry'
+];
 
 
 Canvas.prototype._init = function(config) {
@@ -202,7 +215,7 @@ Canvas.prototype._clear = function() {
 
   // remove all elements
   allElements.forEach(function(element) {
-    var type = Elements.getType(element);
+    var type = getType(element);
 
     if (type === 'root') {
       self.setRootElement(null, true);
@@ -494,7 +507,7 @@ Canvas.prototype._ensureValid = function(type, element) {
 };
 
 Canvas.prototype._setParent = function(element, parent, parentIndex) {
-  Collections.add(parent.children, element, parentIndex);
+  collectionAdd(parent.children, element, parentIndex);
   element.parent = parent;
 };
 
@@ -592,7 +605,7 @@ Canvas.prototype._removeElement = function(element, type) {
   graphicsFactory.remove(element);
 
   // unset parent <-> child relationship
-  Collections.remove(element.parent && element.parent.children, element);
+  collectionRemove(element.parent && element.parent.children, element);
   element.parent = null;
 
   eventBus.fire(type + '.removed', { element: element });

lib/core/ElementFactory.js

@@ -1,18 +1,18 @@
 'use strict';
 
-var Model = require('../model');
+import {
+  create
+} from '../model';
 
-var assign = require('min-dash').assign;
+import { assign } from 'min-dash';
 
 /**
  * A factory for diagram-js shapes
  */
-function ElementFactory() {
+export default function ElementFactory() {
   this._uid = 12;
 }
 
-module.exports = ElementFactory;
-
 
 ElementFactory.prototype.createRoot = function(attrs) {
   return this.create('root', attrs);
@@ -46,5 +46,5 @@ ElementFactory.prototype.create = function(type, attrs) {
     attrs.id = type + '_' + (this._uid++);
   }
 
-  return Model.create(type, attrs);
+  return create(type, attrs);
 };

lib/core/ElementRegistry.js

@@ -2,24 +2,22 @@
 
 var ELEMENT_ID = 'data-element-id';
 
-var svgAttr = require('tiny-svg').attr;
+import { attr as svgAttr } from 'tiny-svg';
 
 
 /**
  * @class
  *
  * A registry that keeps track of all shapes in the diagram.
  */
-function ElementRegistry(eventBus) {
+export default function ElementRegistry(eventBus) {
   this._elements = {};
 
   this._eventBus = eventBus;
 }
 
 ElementRegistry.$inject = [ 'eventBus' ];
 
-module.exports = ElementRegistry;
-
 /**
  * Register a pair of (element, gfx, (secondaryGfx)).
  *

lib/core/EventBus.js

@@ -1,10 +1,12 @@
 'use strict';
 
-var isFunction = require('min-dash').isFunction,
-    isArray = require('min-dash').isArray,
-    isNumber = require('min-dash').isNumber,
-    bind = require('min-dash').bind,
-    assign = require('min-dash').assign;
+import {
+  isFunction,
+  isArray,
+  isNumber,
+  bind,
+  assign
+} from 'min-dash';
 
 var FN_REF = '__fn';
 
@@ -95,16 +97,14 @@ var slice = Array.prototype.slice;
  * console.log(sum); // 3
  * ```
  */
-function EventBus() {
+export default function EventBus() {
   this._listeners = {};
 
   // cleanup on destroy on lowest priority to allow
   // message passing until the bitter end
   this.on('diagram.destroy', 1, this._destroy, this);
 }
 
-module.exports = EventBus;
-
 
 /**
  * Register an event listener for events with the given name.