feat(viewer): allow additional modules to be passed

This enables users to instantiate Viewers/Modelers via

```
new Viewer({
additionalModules: [ ... ]
});
```

to bootstrap their own modules with the viewer without overriding the
existing ones.

lib/Modeler.js

@@ -25,11 +25,11 @@ var initialDiagram =
   '</bpmn:definitions>';
 
 /**
- * @class
- *
  * A modeler for BPMN 2.0 diagrams.
  *
- * @borrows Viewer as Modeler
+ * @class
+ *
+ * @inheritDoc djs.Viewer
  */
 function Modeler(options) {
   Viewer.call(this, options);

lib/Viewer.js

@@ -43,14 +43,16 @@ function checkValidationError(err) {
 }
 
 /**
- * @class
- *
  * A viewer for BPMN 2.0 diagrams
  *
+ * @class
+ *
  * @param {Object} [options] configuration options to pass to the viewer
  * @param {DOMElement} [options.container] the container to render the viewer in, defaults to body.
  * @param {String|Number} [options.width] the width of the viewer
  * @param {String|Number} [options.height] the height of the viewer
+ * @param {Array<didi.Module>} [options.modules] a list of modules to override the default modules
+ * @param {Array<didi.Module>} [options.additionalModules] a list of modules to use with the default modules
  */
 function Viewer(options) {
   this.options = options = options || {};
@@ -186,7 +188,7 @@ Viewer.prototype.importDefinitions = function(definitions, done) {
       this.clear();
     }
 
-    this.diagram = diagram = this._createDiagram(this.options.modules);
+    this.diagram = diagram = this._createDiagram(this.options);
     this.definitions = definitions;
 
     this._init(diagram);
@@ -201,19 +203,23 @@ Viewer.prototype._init = function(diagram) {
   initListeners(diagram, this.__listeners || []);
 };
 
-Viewer.prototype._createDiagram = function(modules) {
+Viewer.prototype._createDiagram = function(options) {
 
-  modules = [].concat(modules || this.getModules());
+  var modules = [].concat(options.modules || this.getModules(), options.additionalModules || []);
 
   // add self as an available service
   modules.unshift({
     bpmnjs: [ 'value', this ]
   });
 
-  return new Diagram({
+  options = _.omit(options, 'additionalModules');
+
+  options = _.extend(options, {
     canvas: { container: this.container },
     modules: modules
   });
+
+  return new Diagram(options);
 };
 
 

lib/import/Importer.js

@@ -4,8 +4,9 @@ var BpmnTreeWalker = require('./BpmnTreeWalker');
 
 
 /**
- * Import the definitions into the given diagram, reporting errors and warnings
- * via the specified callback.
+ * Import the definitions into a diagram.
+ *
+ * Errors and warnings are reported through the specified callback.
  *
  * @param  {Diagram} diagram
  * @param  {ModdleElement} definitions
@@ -34,14 +35,10 @@ function importBpmnDiagram(diagram, definitions, done) {
 
   var walker = new BpmnTreeWalker(visitor);
 
-  try {
-    // import
-    walker.handleDefinitions(definitions);
+  // import
+  walker.handleDefinitions(definitions);
 
-    done(null, warnings);
-  } catch (e) {
-    done(e);
-  }
+  done(null, warnings);
 }
 
 module.exports.importBpmnDiagram = importBpmnDiagram;

test/spec/ViewerSpec.js

@@ -24,10 +24,10 @@ describe('viewer', function() {
 
 
   function createViewer(xml, done) {
-    var renderer = new Viewer({ container: container });
+    var viewer = new Viewer({ container: container });
 
-    renderer.importXML(xml, function(err) {
-      done(err, renderer);
+    viewer.importXML(xml, function(err) {
+      done(err, viewer);
     });
   }
 
@@ -119,14 +119,14 @@ describe('viewer', function() {
       // given
       var xml = fs.readFileSync('test/fixtures/bpmn/empty-definitions.bpmn', 'utf8');
 
-      createViewer(xml, function(err, renderer) {
+      createViewer(xml, function(err, viewer) {
 
         if (err) {
           return done(err);
         }
 
         // when
-        renderer.saveSVG(function(err, svg) {
+        viewer.saveSVG(function(err, svg) {
 
           if (err) {
             return done(err);
@@ -153,4 +153,49 @@ describe('viewer', function() {
 
   });
 
+  describe('configuration', function() {
+
+    var testModules = [
+      { logger: [ 'type', function() { this.called = true; } ] }
+    ];
+
+    // given
+    var xml = fs.readFileSync('test/fixtures/bpmn/empty-definitions.bpmn', 'utf8');
+
+
+    it('should override default modules', function(done) {
+
+      // given
+      var viewer = new Viewer({ container: container, modules: testModules });
+
+      // when
+      viewer.importXML(xml, function(err) {
+
+        // then
+        expect(err.message).toBe('No provider for "bpmnImporter"! (Resolving: bpmnImporter)');
+        done();
+      });
+
+    });
+
+
+    it('should add module to default modules', function(done) {
+
+      // given
+      var viewer = new Viewer({ container: container, additionalModules: testModules });
+
+      // when
+      viewer.importXML(xml, function(err) {
+
+        // then
+        var logger = viewer.get('logger');
+        expect(logger.called).toBe(true);
+
+        done(err);
+      });
+
+    });
+
+  });
+
 });