feat: make ifc importer accessible in ifc loader

Author: agviegas

packages/core/src/fragments/IfcLoader/example.ts

@@ -60,6 +60,17 @@ components.get(OBC.Grids).create(world);
 
 const ifcLoader = components.get(OBC.IfcLoader);
 
+/* MD
+  :::warning What elements of IFC get converted to Fragments?
+
+  For memory efficiency reasons, we don't convert each an every element to fragments by default. You can see the list in IfcImporter.classes and check out the full list [here](https://github.com/ThatOpen/engine_fragment/blob/main/packages/fragments/src/Importers/IfcImporter/src/classes.ts). If you convert an IFC to fragments and miss some elements, you probably need to add their IFC classes to the list. You can access the importer instance in the onIfcImporterInitialized event.
+  :::
+*/
+
+ifcLoader.onIfcImporterInitialized.add((importer) => {
+  console.log(importer.classes);
+});
+
 /* MD
   With the loader in place, it needs to be properly configured. This involves setting up web-ifc (the core library responsible for reading IFC files) to ensure it is ready to convert IFC files into Fragments:
 */

packages/core/src/fragments/IfcLoader/index.ts

@@ -25,6 +25,11 @@ export class IfcLoader extends Component implements Disposable {
    */
   readonly onIfcStartedLoading = new Event<void>();
 
+  /**
+   * An event triggered when the IFC importer is initialized.
+   */
+  readonly onIfcImporterInitialized = new Event<FRAGS.IfcImporter>();
+
   /**
    * An event triggered when the setup process is completed.
    */
@@ -124,6 +129,8 @@ export class IfcLoader extends Component implements Disposable {
     serializer.wasm.absolute = this.settings.wasm.absolute;
     serializer.webIfcSettings = this.settings.webIfc;
 
+    this.onIfcImporterInitialized.trigger(serializer);
+
     if (config?.instanceCallback) config.instanceCallback(serializer);
 
     const bytes = await serializer.process({