fix: worker model loading by preserving use_external_data_format defaults (#138)

* fix: worker model loading by preserving use_external_data_format defaults

* example: update app to use web worker for all models

* chore: bump version

Author: jakobhoeg

.changeset/hungry-areas-strive.md

@@ -0,0 +1,5 @@
+---
+"@browser-ai/transformers-js": patch
+---
+
+fix: worker model loading by preserving use_external_data_format defaults

examples/next-hybrid/app/transformers-js/util/models-config.ts

@@ -26,14 +26,14 @@ export const MODELS: ModelConfig[] = [
     name: "Granite 4.0 350M (Tool calling)",
     device: "webgpu",
     dtype: "fp16",
-    supportsWorker: false,
+    supportsWorker: true,
   },
   {
     id: "onnx-community/LFM2-1.2B-Tool-ONNX",
     name: "LFM2 1.2B-Tool",
     device: "webgpu",
     dtype: "fp16",
-    supportsWorker: false,
+    supportsWorker: true,
   },
   {
     id: "HuggingFaceTB/SmolVLM-256M-Instruct",

packages/vercel/transformers-js/src/chat/transformers-js-language-model.ts

@@ -53,6 +53,11 @@ export interface TransformersJSModelSettings extends Pick<
   PretrainedModelOptions,
   "device" | "dtype"
 > {
+  /**
+   * Optional ONNX external data format toggle.
+   * Keep undefined to use Transformers.js defaults.
+   */
+  use_external_data_format?: boolean;
   /**
    * Progress callback for model initialization
    */
@@ -281,8 +286,14 @@ export class TransformersJSLanguageModel implements LanguageModelV3 {
     onInitProgress?: DownloadProgressCallback,
   ): Promise<void> {
     try {
-      const { isVisionModel, device, dtype, localModelPath, cacheDir } =
-        this.config;
+      const {
+        isVisionModel,
+        device,
+        dtype,
+        localModelPath,
+        cacheDir,
+        use_external_data_format,
+      } = this.config;
 
       // Configure transformers.js environment settings
       if (localModelPath) {
@@ -309,6 +320,9 @@ export class TransformersJSLanguageModel implements LanguageModelV3 {
           AutoModelForVision2Seq.from_pretrained(this.modelId, {
             dtype: resolvedDtype,
             device: resolvedDevice,
+            ...(use_external_data_format !== undefined
+              ? { use_external_data_format }
+              : {}),
             progress_callback,
           }),
         ]);
@@ -322,6 +336,9 @@ export class TransformersJSLanguageModel implements LanguageModelV3 {
           AutoModelForCausalLM.from_pretrained(this.modelId, {
             dtype: resolvedDtype,
             device: resolvedDevice,
+            ...(use_external_data_format !== undefined
+              ? { use_external_data_format }
+              : {}),
             progress_callback,
           }),
         ]);
@@ -771,6 +788,7 @@ export class TransformersJSLanguageModel implements LanguageModelV3 {
           modelId: this.modelId,
           dtype: this.config.dtype,
           device: this.config.device,
+          use_external_data_format: this.config.use_external_data_format,
           isVisionModel: this.config.isVisionModel,
         },
       });

packages/vercel/transformers-js/src/chat/transformers-js-worker-handler.ts

@@ -54,7 +54,7 @@ class ModelManager {
       modelId,
       dtype = "auto",
       device = "auto",
-      use_external_data_format = false,
+      use_external_data_format,
       isVisionModel = false,
     } = config;
 
@@ -93,7 +93,9 @@ class ModelManager {
       AutoModelForCausalLM.from_pretrained(modelId, {
         dtype: options.dtype,
         device: options.device,
-        use_external_data_format: options.use_external_data_format,
+        ...(options.use_external_data_format !== undefined
+          ? { use_external_data_format: options.use_external_data_format }
+          : {}),
         progress_callback: options.progressCallback,
       }),
     ]);
@@ -116,7 +118,9 @@ class ModelManager {
       AutoModelForVision2Seq.from_pretrained(modelId, {
         dtype: options.dtype || "fp32",
         device: options.device || "webgpu",
-        use_external_data_format: options.use_external_data_format,
+        ...(options.use_external_data_format !== undefined
+          ? { use_external_data_format: options.use_external_data_format }
+          : {}),
         progress_callback: options.progressCallback,
       }),
     ]);

packages/vercel/transformers-js/src/chat/transformers-js-worker-types.ts

@@ -27,6 +27,7 @@ export interface WorkerLoadData {
   modelId?: string;
   dtype?: PretrainedModelOptions["dtype"];
   device?: PretrainedModelOptions["device"];
+  use_external_data_format?: boolean;
   isVisionModel?: boolean;
 }