try catch AbortError

Author: Neet-Nestor

examples/abort-reload/src/get_started.js

@@ -1,4 +1,5 @@
 import * as webllm from "@mlc-ai/web-llm";
+import { error } from "loglevel";
 
 let engine;
 
@@ -25,5 +26,7 @@ async function main() {
 main();
 setTimeout(() => {
   console.log("calling unload");
-  engine.unload();
+  engine.unload().catch((err) => {
+    console.log(err);
+  });
 }, 5000);

src/engine.ts

@@ -145,7 +145,25 @@ export class MLCEngine implements MLCEngineInterface {
    */
   async reload(modelId: string, chatOpts?: ChatOptions): Promise<void> {
     await this.unload();
+    this.reloadController = new AbortController();
 
+    try {
+      await this.reloadInternal(modelId, chatOpts);
+    } catch (error) {
+      if (error instanceof DOMException && error.name === "AbortError") {
+        log.warn("Reload() is aborted.", error.message);
+        return;
+      }
+      throw error;
+    } finally {
+      this.reloadController = undefined;
+    }
+  }
+
+  private async reloadInternal(
+    modelId: string,
+    chatOpts?: ChatOptions,
+  ): Promise<void> {
     this.logitProcessor = this.logitProcessorRegistry?.get(modelId);
     const tstart = performance.now();
 
@@ -157,8 +175,6 @@ export class MLCEngine implements MLCEngineInterface {
       throw new ModelNotFoundError(modelId);
     };
 
-    this.reloadController = new AbortController();
-
     const modelRecord = findModelRecord();
     const baseUrl =
       typeof document !== "undefined"
@@ -209,7 +225,6 @@ export class MLCEngine implements MLCEngineInterface {
         // rely on the normal caching strategy
         return (await fetch(new URL(wasmUrl, baseUrl).href)).arrayBuffer();
       } else {
-        // use cache
         return await wasmCache.fetchWithCache(
           wasmUrl,
           "arraybuffer",