add custom importer to handle loop input/output

app/app.js

@@ -41,8 +41,33 @@ try {
   throw error;
 }
 
+/* The default importer drops the loop data inputs and outputs on multi instance tasks.
+ * They don't reference anything in our diagrams (which is a problem we should tackle, but not essential right now).
+ * This is probably a terrible solution, but given that the modifications happen every time a diagram is parsed,
+ * ia a locally defined function inside the parser, I don't see any other way of dealing with it than to just
+ * intercept the parsed results and patch them up again.
+ */
+
+function importWithUnresolvedRefs(bpmnModeler, xml) {
+  bpmnModeler._moddle.fromXML(xml).then((result) => {
+    const refs = result.references.filter(r => r.property === 'bpmn:loopDataInputRef' || r.property === 'bpmn:loopDataOutputRef');
+    const desc = bpmnModeler._moddle.registry.getEffectiveDescriptor('bpmn:ItemAwareElement');
+    refs.forEach(ref => {
+      const props = {
+        id: ref.id,
+        name: ref.id ? typeof(ref.name) === 'undefined': ref.name,
+      };
+      let elem = bpmnModeler._moddle.create(desc, props);
+      elem.$parent = ref.element;
+      ref.element.set(ref.property, elem);
+    });
+    bpmnModeler.importDefinitions(result.rootElement);
+    bpmnModeler.open();
+  });
+};
+
 // import XML
-bpmnModeler.importXML(diagramXML).then(() => {});
+importWithUnresolvedRefs(bpmnModeler, diagramXML);
 
 /**
  * It is possible to populate certain components using API calls to
@@ -195,4 +220,4 @@ bpmnModeler.on('spiff.callactivity.search', (event) => {
 // This handles the download and upload buttons - it isn't specific to
 // the BPMN modeler or these extensions, just a quick way to allow you to
 // create and save files, so keeping it outside the example.
-setupFileOperations(bpmnModeler);
+setupFileOperations(bpmnModeler, importWithUnresolvedRefs);

app/fileOperations.js

@@ -7,11 +7,12 @@ import FileSaver from 'file-saver';
  * easily from the editor for testing purposes.
  * -----------------------------------------
  */
-export default function setupFileOperations(bpmnModeler) {
+export default function setupFileOperations(bpmnModeler, importWithUnresolvedRefs) {
   /**
    * Just a quick bit of code so we can save the XML that is output.
    * Helps for debugging against other libraries (like SpiffWorkflow)
    */
+
   const btn = document.getElementById('downloadButton');
   btn.addEventListener('click', (_event) => {
     saveXML();
@@ -29,12 +30,8 @@ export default function setupFileOperations(bpmnModeler) {
    */
   const uploadBtn = document.getElementById('uploadButton');
   uploadBtn.addEventListener('click', (_event) => {
-    openFile(displayFile);
+    openFile(bpmnModeler, importWithUnresolvedRefs);
   });
-
-  function displayFile(contents) {
-    bpmnModeler.importXML(contents).then(() => {});
-  }
 }
 
 function clickElem(elem) {
@@ -59,7 +56,7 @@ function clickElem(elem) {
   elem.dispatchEvent(eventMouse);
 }
 
-export function openFile(func) {
+export function openFile(bpmnModeler, importWithUnresolvedRefs) {
   const readFile = function readFileCallback(e) {
     const file = e.target.files[0];
     if (!file) {
@@ -68,7 +65,7 @@ export function openFile(func) {
     const reader = new FileReader();
     reader.onload = function onloadCallback(onloadEvent) {
       const contents = onloadEvent.target.result;
-      fileInput.func(contents);
+      importWithUnresolvedRefs(bpmnModeler, contents);
       document.body.removeChild(fileInput);
     };
     reader.readAsText(file);
@@ -77,7 +74,6 @@ export function openFile(func) {
   fileInput.type = 'file';
   fileInput.style.display = 'none';
   fileInput.onchange = readFile;
-  fileInput.func = func;
   document.body.appendChild(fileInput);
   clickElem(fileInput);
 }