Fix subgraph issue

src/diagrams/flowchart/flowDb.js

@@ -318,7 +318,7 @@ export const addSubGraph = function (list, title) {
 
     return a.filter(function (item) {
       const type = typeof item
-      if (item === ' ') {
+      if (item.trim() === '') {
         return false
       }
       if (type in prims) { return prims[type].hasOwnProperty(item) ? false : (prims[type][item] = true) } else { return objs.indexOf(item) >= 0 ? false : objs.push(item) }
@@ -329,7 +329,7 @@ export const addSubGraph = function (list, title) {
 
   nodeList = uniq(nodeList.concat.apply(nodeList, list))
 
-  const subGraph = { id: 'subGraph' + subCount, nodes: nodeList, title: title }
+  const subGraph = { id: 'subGraph' + subCount, nodes: nodeList, title: title.trim() }
   subGraphs.push(subGraph)
   subCount = subCount + 1
   return subGraph.id

src/diagrams/flowchart/parser/flow.jison

@@ -225,7 +225,7 @@ statement
     {$$=[];}
     | clickStatement separator
     {$$=[];}
-    | subgraph  text separator document end
+    | subgraph text separator document end
     {$$=yy.addSubGraph($4,$2);}
     | subgraph separator document end
     {$$=yy.addSubGraph($3,undefined);}

src/diagrams/flowchart/parser/flow.spec.js

@@ -22,6 +22,17 @@ describe('when parsing ', function () {
     expect(edges[0].text).toBe('')
   })
 
+  it('should handle subgraph with tab indentation', function () {
+    const res = flow.parser.parse('graph TB\nsubgraph One\n\ta1-->a2\nend')
+    const subgraphs = flow.parser.yy.getSubGraphs()
+    expect(subgraphs.length).toBe(1)
+    const subgraph = subgraphs[0]
+    expect(subgraph.nodes.length).toBe(2)
+    expect(subgraph.nodes[0]).toBe('a1')
+    expect(subgraph.nodes[1]).toBe('a2')
+    expect(subgraph.title).toBe('One')
+  })
+
   it('should handle angle bracket ' > ' as direction LR', function () {
     const res = flow.parser.parse('graph >;A-->B;')