From 2783dc3032be35fa2c51f9969f355f8e24ed438a Mon Sep 17 00:00:00 2001
From: PylotLight <lochois@gmail.com>
Date: Mon, 30 Dec 2024 15:41:29 +1100
Subject: [PATCH] add dynamic import and optional dep

---
 libs/langchain-community/package.json         |  3 ++
 .../src/embeddings/hf_transformers.ts         | 39 +++++++++++++++++--
 2 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/libs/langchain-community/package.json b/libs/langchain-community/package.json
index 985282258cbe..4b32aa9abf36 100644
--- a/libs/langchain-community/package.json
+++ b/libs/langchain-community/package.json
@@ -713,6 +713,9 @@
       "optional": true
     }
   },
+  "optionalDependencies": {
+  "@xenova/transformers": "^2.17.2"
+  },
   "publishConfig": {
     "access": "public"
   },
diff --git a/libs/langchain-community/src/embeddings/hf_transformers.ts b/libs/langchain-community/src/embeddings/hf_transformers.ts
index 8996e477cd40..4eb14eca1896 100644
--- a/libs/langchain-community/src/embeddings/hf_transformers.ts
+++ b/libs/langchain-community/src/embeddings/hf_transformers.ts
@@ -8,6 +8,7 @@ import { chunkArray } from "@langchain/core/utils/chunk_array";
 
 export interface HuggingFaceTransformersEmbeddingsParams
   extends EmbeddingsParams {
+
   /**
    * Model name to use
    * Alias for `model`
@@ -124,13 +125,45 @@ export class HuggingFaceTransformersEmbeddings
   }
 
   private async runEmbedding(texts: string[]) {
-    const pipe = await (this.pipelinePromise ??= (
-      await import("@huggingface/transformers")
-    ).pipeline("feature-extraction", this.model, this.pretrainedOptions));
+    const pipe = await this.getPipeline();
 
     return this.caller.call(async () => {
       const output = await pipe(texts, this.pipelineOptions);
       return output.tolist();
     });
   }
+
+  private async getPipeline() {
+    if (!this.pipelinePromise) {
+      try {
+        // Try importing the new package
+        const { pipeline } = await import("@huggingface/transformers");
+        this.pipelinePromise = pipeline(
+          "feature-extraction",
+          this.model,
+          this.pretrainedOptions
+        );
+      } catch (e) {
+        console.warn(
+          "Failed to load @huggingface/transformers. Falling back to @xenova/transformers."
+        );
+  
+        try {
+          // Fallback to the old package
+          const { pipeline } = await import("@xenova/transformers");
+          this.pipelinePromise = pipeline(
+            "feature-extraction",
+            this.model,
+            this.pretrainedOptions
+          );
+        } catch (fallbackError) {
+          throw new Error(
+            "Failed to load both @huggingface/transformers and @xenova/transformers. Ensure one of them is installed."
+          );
+        }
+      }
+    }
+    return this.pipelinePromise;
+  }
+  
 }