Test and debugbar tools to simulate single nodes appearing

client/app/scripts/charts/__tests__/node-layout-test.js

@@ -35,6 +35,21 @@ describe('NodesLayout', () => {
         'n2-n4': {id: 'n2-n4', source: 'n2', target: 'n4'}
       })
     },
+    addNode15: {
+      nodes: fromJS({
+        n1: {id: 'n1'},
+        n2: {id: 'n2'},
+        n3: {id: 'n3'},
+        n4: {id: 'n4'},
+        n5: {id: 'n5'}
+      }),
+      edges: fromJS({
+        'n1-n3': {id: 'n1-n3', source: 'n1', target: 'n3'},
+        'n1-n4': {id: 'n1-n4', source: 'n1', target: 'n4'},
+        'n1-n5': {id: 'n1-n5', source: 'n1', target: 'n5'},
+        'n2-n4': {id: 'n2-n4', source: 'n2', target: 'n4'}
+      })
+    },
     removeEdge24: {
       nodes: fromJS({
         n1: {id: 'n1'},
@@ -86,6 +101,19 @@ describe('NodesLayout', () => {
       edges: fromJS({
         'n1-n4': {id: 'n1-n4', source: 'n1', target: 'n4'}
       })
+    },
+    singlePortrait6: {
+      nodes: fromJS({
+        n1: {id: 'n1'},
+        n2: {id: 'n2'},
+        n3: {id: 'n3'},
+        n4: {id: 'n4'},
+        n5: {id: 'n5'},
+        n6: {id: 'n6'}
+      }),
+      edges: fromJS({
+        'n1-n4': {id: 'n1-n4', source: 'n1', target: 'n4'}
+      })
     }
   };
 
@@ -282,4 +310,65 @@ describe('NodesLayout', () => {
     expect(nodes.n1.x).toBeLessThan(nodes.n5.x);
     expect(nodes.n2.x).toEqual(nodes.n5.x);
   });
+
+  it('renders an additional single node in single nodes group', () => {
+    let result = NodesLayout.doLayout(
+      nodeSets.singlePortrait.nodes,
+      nodeSets.singlePortrait.edges);
+
+    nodes = result.nodes.toJS();
+
+    // first square row on same level as top-most other node
+    expect(nodes.n1.y).toEqual(nodes.n2.y);
+    expect(nodes.n1.y).toEqual(nodes.n3.y);
+    expect(nodes.n4.y).toEqual(nodes.n5.y);
+
+    // all singles right to other nodes
+    expect(nodes.n1.x).toEqual(nodes.n4.x);
+    expect(nodes.n1.x).toBeLessThan(nodes.n2.x);
+    expect(nodes.n1.x).toBeLessThan(nodes.n3.x);
+    expect(nodes.n1.x).toBeLessThan(nodes.n5.x);
+    expect(nodes.n2.x).toEqual(nodes.n5.x);
+
+    options.cachedLayout = result;
+    options.nodeCache = options.nodeCache.merge(result.nodes);
+    options.edgeCache = options.edgeCache.merge(result.edge);
+
+    result = NodesLayout.doLayout(
+      nodeSets.singlePortrait6.nodes,
+      nodeSets.singlePortrait6.edges,
+      options
+    );
+
+    nodes = result.nodes.toJS();
+
+    expect(nodes.n1.x).toBeLessThan(nodes.n2.x);
+    expect(nodes.n1.x).toBeLessThan(nodes.n3.x);
+    expect(nodes.n1.x).toBeLessThan(nodes.n5.x);
+    expect(nodes.n1.x).toBeLessThan(nodes.n6.x);
+  });
+
+  it('adds a new node to existing layout in a line', () => {
+    let result = NodesLayout.doLayout(
+      nodeSets.initial4.nodes,
+      nodeSets.initial4.edges);
+
+    nodes = result.nodes.toJS();
+
+    coords = getNodeCoordinates(result.nodes);
+    options.cachedLayout = result;
+    options.nodeCache = options.nodeCache.merge(result.nodes);
+    options.edgeCache = options.edgeCache.merge(result.edge);
+
+    result = NodesLayout.doLayout(
+      nodeSets.addNode15.nodes,
+      nodeSets.addNode15.edges,
+      options
+    );
+
+    nodes = result.nodes.toJS();
+
+    expect(nodes.n1.x).toBeGreaterThan(nodes.n5.x);
+    expect(nodes.n1.y).toEqual(nodes.n5.y);
+  });
 });

client/app/scripts/charts/nodes-layout.js

@@ -274,6 +274,13 @@ export function hasUnseenNodes(nodes, cache) {
   return hasUnseen;
 }
 
+function hasNewSingleNode(nodes, cache) {
+  return (ImmSet
+    .fromKeys(nodes)
+    .subtract(ImmSet.fromKeys(cache))
+    .every(key => nodes.getIn([key, 'degree']) === 0));
+}
+
 /**
  * Determine if edge has same endpoints in new nodes as well as in the nodeCache
  * @param  {Map}  edge      Edge with source and target
@@ -364,9 +371,14 @@ export function doLayout(immNodes, immEdges, opts) {
   } else {
     const graph = cache.graph;
     const nodesWithDegrees = updateNodeDegrees(immNodes, immEdges);
-    layout = runLayoutEngine(graph, nodesWithDegrees, immEdges, opts);
-    if (!layout) {
-      return layout;
+    if (hasNewSingleNode(nodesWithDegrees, nodeCache)) {
+      layout = cloneLayout(cachedLayout, immNodes, immEdges);
+      layout = copyLayoutProperties(layout, nodeCache, edgeCache);
+    } else {
+      layout = runLayoutEngine(graph, nodesWithDegrees, immEdges, opts);
+      if (!layout) {
+        return layout;
+      }
     }
     layout = layoutSingleNodes(layout, opts);
     layout = shiftLayoutToCenter(layout, opts);