<script>
 import go from 'gojs';
 let $ = go.GraphObject.make; // 后面很多用到该变量来初始化diagram
 export default{
  name: 'diagram',
  props: ['modelData'], // accept model data as a parameter
  data() {
   return {
   diagram: null,
   }; 
  }, // provide access to the GoJS Diagram

mounted: function() {
  let self = this;
  let myDiagram =
   $(go.Diagram, this.$el,
   {
    'initialContentAlignment': go.Spot.Center,
    'isEnabled': false, // 是否可拖拽，默认为是
    // 'toolManager.mouseWheelBehavior': go.ToolManager.WheelNone,
    'allowLink': false, 
    'allowMove': false,
    'allowRelink': false, // 由于项目只想展示数据，我禁用了大部分图像交互操作，具体可参看官网API
    'layout': $(go.TreeLayout, {angle: 0, arrangement: go.TreeLayout.ArrangementHorizontal}),  // angle可控制图像展示方向
    'undoManager.isEnabled': true,
    // Model ChangedEvents get passed up to component users
    'ChangedSelection': function(e) {
     self.$emit('changed-selection', e); 
    },
   });
   
  myDiagram.nodeTemplate = // 节点的初始化设置
   $(go.Node, 'Auto',
   $(go.Shape, // 节点形状设置
   {
    fill: 'white', strokeWidth: 1,
    portId: '', fromLinkable: true, toLinkable: true, cursor: 'pointer',
   },
    new go.Binding('fill', '', this.nodeColorConverter)), // nodeColorConverter是我自定义函数，根据节点状态设置节点的背景颜色
   $(go.TextBlock, // 节点提示文字设置
    {margin: 16, editable: false},
    new go.Binding('text').makeTwoWay())
   );

  myDiagram.linkTemplate =
   $(go.Link,
   {relinkableFrom: true, relinkableTo: true},
   $(go.Shape, // 连线形状设置
   {strokeWidth: 2},
   new go.Binding('stroke', '', this.linkColorConverter)), // 连线的颜色设置
   $(go.Shape, // arrowhead
   {toArrow: 'Triangle', stroke: null, scale: 1.5}, // 箭头设置
   new go.Binding('fill', '', this.linkColorConverter))
   );
  
  myDiagram.groupTemplate = // 分组的初始化
   $(go.Group, 'Auto',
    { // define the group's internal layout
    layout: $(go.TreeLayout,
       {angle: 90, arrangement: go.TreeLayout.ArrangementVertical, isRealtime: false}),
    // the group begins unexpanded;
    // upon expansion, a Diagram Listener will generate contents for the group
    // when a group is expanded, if it contains no parts, generate a subGraph inside of it
    // subGraphExpandedChanged: function(group) {
    // if (group.memberParts.count === 0) {
    //  randomGroup(group.data.key);
    // }
    // },
    },
   $(go.Shape, 'Rectangle',
    {fill: null, stroke: 'gray', strokeWidth: 2}),
   $(go.Panel, 'Vertical',
    {defaultAlignment: go.Spot.Left, margin: 4},
    $(go.Panel, 'Horizontal',
    {defaultAlignment: go.Spot.Top},
    $('SubGraphExpanderButton', {alignment: go.Spot.Top, margin: 5}),
    // the SubGraphExpanderButton is a panel that functions as a button to expand or collapse the subGraph
    $(go.TextBlock,
     {
     font: 'Bold 14px Sans-Serif',
     margin: 10,
     },
     new go.Binding('text', 'text'))
    ),
   // create a placeholder to represent the area where the contents of the group are
    $(go.Placeholder,
    {padding: new go.Margin(0, 10)}),
   ) // end Vertical Panel
   ); // end Group

   // generate the initial model
  this.diagram = myDiagram;
  this.updateModel(this.modelData);

watch: {
  modelData: function(val) { 
   this.updateModel(val); 
  },
  },
  methods: {
  model: function() { 
   return this.diagram.model; 
  },
  updateModel: function(val) {
   // No GoJS transaction permitted when replacing Diagram.model.
   if (val instanceof go.Model) {
   this.diagram.model = val;
   } else {
   let m = new go.GraphLinksModel();
   if (val) {
    for (let p in val) {
    if (val[p]) {
     m[p] = val[p];
    }
    }
   }
   this.diagram.model = m;
   }
  },
  updateDiagramFromData: function() {
   this.diagram.startTransaction();
   // This is very general but very inefficient.
   // It would be better to modify the diagramData data by calling
   // Model.setDataProperty or Model.addNodeData, et al.
   this.diagram.updateAllRelationshipsFromData();
   this.diagram.updateAllTargetBindings();
   this.diagram.commitTransaction('updated');
  },
  },
 };
</script>

updateDiagramFromData: function() {
   this.$refs.diag.updateDiagramFromData(); // 数据变化时调用组件中的更新方法
  },
changedSelection: function(e) {
   let node = e.diagram.selection.first();
   if (node instanceof go.Node) {
   this.currentNode = node;
   this.currentNodeText = node.data.text;
   this.selectNode(node.data);
   } else {
   this.currentNode = null;
   this.currentNodeText = '';
   }
  },

无分组：
 "nodeDataArray": [ 
{"key":1, "text":"Alpha", "color":"lightblue"},
{"key":2, "text":"Beta", "color":"orange"},
{"key":3, "text":"Gamma", "color":"lightgreen"},
{"key":4, "text":"Delta", "color":"pink"}
 ]
 "linkDataArray": [ 
{"from":1, "to":2},
{"from":1, "to":3},
{"from":3, "to":4}
 ]
有分组：
 var nodeDataArray = [
 { key: "Alpha" },
 { key: "Beta", group: "Omega" },
 { key: "Gamma", group: "Omega" },
 { key: "Omega", isGroup: true }, 
 { key: "Delta" }
 ];
 var linkDataArray = [
 { from: "Alpha", to: "Beta" }, 
 { from: "Beta", to: "Gamma" }, 
 { from: "Omega", to: "Delta" } 
 ];