Fix multiple loading start with no progress manager (#139)

mml-io · Nov 28, 2023 · 6b7b0b7 · 6b7b0b7
1 parent cec2547
commit 6b7b0b7
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Showing 2 changed files with 12 additions and 0 deletions.
diff --git a/packages/mml-web/src/loading/LoadingInstanceManager.ts b/packages/mml-web/src/loading/LoadingInstanceManager.ts
@@ -11,6 +11,10 @@ export class LoadingInstanceManager {
 
   public start(loadingProgressManager: LoadingProgressManager | null, url: string) {
     if (this.currentlyLoadingProgressManager !== null) {
+      if (this.currentlyLoadingProgressManager === noManagerSymbol && !loadingProgressManager) {
+        // Already loading with no progress manager, and no progress manager provided - do nothing
+        return;
+      }
       if (this.currentlyLoadingProgressManager !== loadingProgressManager) {
         throw new Error("Already loading with a different progress manager");
       }

diff --git a/packages/mml-web/test/LoadingInstanceManager.test.ts b/packages/mml-web/test/LoadingInstanceManager.test.ts
@@ -33,6 +33,14 @@ describe("LoadingInstanceManager", () => {
     loadingInstanceManager.finish();
   });
 
+  test("load with no progress manager", () => {
+    // Just needs to not error
+    const loadingInstanceManager = new LoadingInstanceManager("test");
+    loadingInstanceManager.start(null, "http://example.com/foo");
+    loadingInstanceManager.start(null, "http://example.com/bar");
+    loadingInstanceManager.finish();
+  });
+
   test("abort load", () => {
     const mockLoadingProgressManager = {
       addLoadingAsset: jest.fn(),