replacing all ES6 imports with CJS require calls (#3063)

* replacing all ES6 imports with CJS require calls
resolves #2934
used the following regex to apply the changes in lib:
s/import\s+(\w+)\s+from\s+(.*);\s*$/var $1 = require($2).default;/
s/import\s+(\w+)\s+from\s+(.*)\s*$/var $1 = require($2).default;/

* cleaning up inconsistencies

lib/network/Network.js

@@ -10,24 +10,24 @@ let gephiParser = require('./gephiParser');
 let Activator = require('../shared/Activator');
 let locales = require('./locales');
 
-import  Images              from './Images';
-import  Groups              from './modules/Groups';
-import  NodesHandler        from './modules/NodesHandler';
-import  EdgesHandler        from './modules/EdgesHandler';
-import  PhysicsEngine       from './modules/PhysicsEngine';
-import  ClusterEngine       from './modules/Clustering';
-import  CanvasRenderer      from './modules/CanvasRenderer';
-import  Canvas              from './modules/Canvas';
-import  View                from './modules/View';
-import  InteractionHandler  from './modules/InteractionHandler';
-import  SelectionHandler    from "./modules/SelectionHandler";
-import  LayoutEngine        from "./modules/LayoutEngine";
-import  ManipulationSystem  from "./modules/ManipulationSystem";
-import  Configurator        from "./../shared/Configurator";
-import  Validator           from "./../shared/Validator";
-import  {printStyle}        from "./../shared/Validator";
-import  {allOptions, configureOptions} from './options.js';
-import  KamadaKawai         from "./modules/KamadaKawai.js"
+var Images = require('./Images').default;
+var Groups = require('./modules/Groups').default;
+var NodesHandler = require('./modules/NodesHandler').default;
+var EdgesHandler = require('./modules/EdgesHandler').default;
+var PhysicsEngine = require('./modules/PhysicsEngine').default;
+var ClusterEngine = require('./modules/Clustering').default;
+var CanvasRenderer = require('./modules/CanvasRenderer').default;
+var Canvas = require('./modules/Canvas').default;
+var View = require('./modules/View').default;
+var InteractionHandler = require('./modules/InteractionHandler').default;
+var SelectionHandler = require("./modules/SelectionHandler").default;
+var LayoutEngine = require("./modules/LayoutEngine").default;
+var ManipulationSystem = require("./modules/ManipulationSystem").default;
+var Configurator = require("./../shared/Configurator").default;
+var Validator = require("./../shared/Validator").default;
+var {printStyle} = require('./../shared/Validator');
+var {allOptions, configureOptions} = require('./options.js');
+var KamadaKawai = require("./modules/KamadaKawai.js").default;
 
 
 /**

lib/network/modules/Clustering.js

@@ -1,6 +1,6 @@
 let util = require("../../util");
-import NetworkUtil from '../NetworkUtil';
-import Cluster from './components/nodes/Cluster'
+var NetworkUtil = require('../NetworkUtil').default;
+var Cluster = require('./components/nodes/Cluster').default;
 
 class ClusterEngine {
   constructor(body) {

lib/network/modules/EdgesHandler.js

@@ -2,8 +2,8 @@ var util = require("../../util");
 var DataSet = require('../../DataSet');
 var DataView = require('../../DataView');
 
-import Edge  from "./components/Edge"
-import Label from "./components/shared/Label"
+var Edge = require("./components/Edge").default;
+var Label = require("./components/shared/Label").default;
 
 class EdgesHandler {
   constructor(body, images, groups) {

lib/network/modules/InteractionHandler.js

@@ -1,7 +1,7 @@
 let util = require('../../util');
 
-import NavigationHandler from './components/NavigationHandler'
-import Popup             from './../../shared/Popup'
+var NavigationHandler = require('./components/NavigationHandler').default;
+var Popup = require('./../../shared/Popup').default;
 
 class InteractionHandler {
   constructor(body, canvas, selectionHandler) {

lib/network/modules/LayoutEngine.js

@@ -1,7 +1,7 @@
 'use strict';
 
 let util = require('../../util');
-import NetworkUtil from '../NetworkUtil';
+var NetworkUtil = require('../NetworkUtil').default;
 
 
 /**

lib/network/modules/NodesHandler.js

@@ -2,8 +2,8 @@ let util = require("../../util");
 let DataSet = require('../../DataSet');
 let DataView = require('../../DataView');
 
-import Node  from "./components/Node";
-import Label from "./components/shared/Label";
+var Node = require("./components/Node").default;
+var Label = require("./components/shared/Label").default;
 
 class NodesHandler {
   constructor(body, images, groups, layoutEngine) {

lib/network/modules/PhysicsEngine.js

@@ -1,11 +1,11 @@
-import BarnesHutSolver                      from './components/physics/BarnesHutSolver';
-import Repulsion                            from './components/physics/RepulsionSolver';
-import HierarchicalRepulsion                from './components/physics/HierarchicalRepulsionSolver';
-import SpringSolver                         from './components/physics/SpringSolver';
-import HierarchicalSpringSolver             from './components/physics/HierarchicalSpringSolver';
-import CentralGravitySolver                 from './components/physics/CentralGravitySolver';
-import ForceAtlas2BasedRepulsionSolver      from './components/physics/FA2BasedRepulsionSolver';
-import ForceAtlas2BasedCentralGravitySolver from './components/physics/FA2BasedCentralGravitySolver';
+var BarnesHutSolver = require('./components/physics/BarnesHutSolver').default;
+var Repulsion = require('./components/physics/RepulsionSolver').default;
+var HierarchicalRepulsion = require('./components/physics/HierarchicalRepulsionSolver').default;
+var SpringSolver = require('./components/physics/SpringSolver').default;
+var HierarchicalSpringSolver = require('./components/physics/HierarchicalSpringSolver').default;
+var CentralGravitySolver = require('./components/physics/CentralGravitySolver').default;
+var ForceAtlas2BasedRepulsionSolver = require('./components/physics/FA2BasedRepulsionSolver').default;
+var ForceAtlas2BasedCentralGravitySolver = require('./components/physics/FA2BasedCentralGravitySolver').default;
 
 var util = require('../../util');
 

lib/network/modules/SelectionHandler.js

@@ -1,5 +1,5 @@
-import Node from './components/Node';
-import Edge from './components/Edge';
+var Node = require('./components/Node').default;
+var Edge = require('./components/Edge').default;
 
 let util = require('../../util');
 

lib/network/modules/View.js

@@ -1,6 +1,6 @@
 let util = require('../../util');
 
-import NetworkUtil from '../NetworkUtil';
+var NetworkUtil = require('../NetworkUtil').default;
 
 class View {
   constructor(body, canvas) {

lib/network/modules/components/Edge.js

@@ -1,10 +1,10 @@
 var util = require('../../../util');
 
-import Label              from './shared/Label'
-import CubicBezierEdge    from './edges/CubicBezierEdge'
-import BezierEdgeDynamic  from './edges/BezierEdgeDynamic'
-import BezierEdgeStatic   from './edges/BezierEdgeStatic'
-import StraightEdge       from './edges/StraightEdge'
+var Label = require('./shared/Label').default;
+var CubicBezierEdge = require('./edges/CubicBezierEdge').default;
+var BezierEdgeDynamic = require('./edges/BezierEdgeDynamic').default;
+var BezierEdgeStatic = require('./edges/BezierEdgeStatic').default;
+var StraightEdge = require('./edges/StraightEdge').default;
 
 /**
  * @class Edge

lib/network/modules/components/Node.js

@@ -1,23 +1,23 @@
 var util = require('../../../util');
 
-import Label from './shared/Label'
-
-import Box           from './nodes/shapes/Box'
-import Circle        from './nodes/shapes/Circle'
-import CircularImage from './nodes/shapes/CircularImage'
-import Database      from './nodes/shapes/Database'
-import Diamond       from './nodes/shapes/Diamond'
-import Dot           from './nodes/shapes/Dot'
-import Ellipse       from './nodes/shapes/Ellipse'
-import Icon          from './nodes/shapes/Icon'
-import Image         from './nodes/shapes/Image'
-import Square        from './nodes/shapes/Square'
-import Star          from './nodes/shapes/Star'
-import Text          from './nodes/shapes/Text'
-import Triangle      from './nodes/shapes/Triangle'
-import TriangleDown  from './nodes/shapes/TriangleDown'
-import  Validator    from "../../../shared/Validator";
-import  {printStyle} from "../../../shared/Validator";
+var Label = require('./shared/Label').default;
+
+var Box = require('./nodes/shapes/Box').default;
+var Circle = require('./nodes/shapes/Circle').default;
+var CircularImage = require('./nodes/shapes/CircularImage').default;
+var Database = require('./nodes/shapes/Database').default;
+var Diamond = require('./nodes/shapes/Diamond').default;
+var Dot = require('./nodes/shapes/Dot').default;
+var Ellipse = require('./nodes/shapes/Ellipse').default;
+var Icon = require('./nodes/shapes/Icon').default;
+var Image = require('./nodes/shapes/Image').default;
+var Square = require('./nodes/shapes/Square').default;
+var Star = require('./nodes/shapes/Star').default;
+var Text = require('./nodes/shapes/Text').default;
+var Triangle = require('./nodes/shapes/Triangle').default;
+var TriangleDown = require('./nodes/shapes/TriangleDown').default;
+var Validator = require("../../../shared/Validator").default;
+var { printStyle } = require("../../../shared/Validator");
 
 
 /**

lib/shared/Configurator.js

@@ -1,6 +1,6 @@
 var util = require('../util');
 
-import ColorPicker from './ColorPicker'
+var ColorPicker = require('./ColorPicker').default;
 
 /**
  * The way this works is for all properties of this.possible options, you can supply the property name in any form to list the options.

lib/timeline/Graph2d.js

@@ -15,8 +15,8 @@ var printStyle = require('../shared/Validator').printStyle;
 var allOptions = require('./optionsGraph2d').allOptions;
 var configureOptions = require('./optionsGraph2d').configureOptions;
 
-import Configurator from '../shared/Configurator';
-import Validator from '../shared/Validator';
+var Configurator = require('../shared/Configurator').default;
+var Validator = require('../shared/Validator').default;
 
 /**
  * Create a timeline visualization

lib/timeline/Timeline.js

@@ -15,8 +15,8 @@ var printStyle = require('../shared/Validator').printStyle;
 var allOptions = require('./optionsTimeline').allOptions;
 var configureOptions = require('./optionsTimeline').configureOptions;
 
-import Configurator from '../shared/Configurator';
-import Validator from '../shared/Validator';
+var Configurator = require('../shared/Configurator').default;
+var Validator = require('../shared/Validator').default;
 
 
 /**

lib/timeline/component/ItemSet.js

@@ -10,7 +10,7 @@ var BoxItem = require('./item/BoxItem');
 var PointItem = require('./item/PointItem');
 var RangeItem = require('./item/RangeItem');
 var BackgroundItem = require('./item/BackgroundItem');
-import Popup from '../../shared/Popup';
+var Popup = require('../../shared/Popup').default;
 
 
 var UNGROUPED = '__ungrouped__';   // reserved group id for ungrouped items