Node - Fix encoding pad

bindings/node/lib/bindings/raw-encoding.test.ts

@@ -1,5 +1,6 @@
 import { promisify } from "util";
 
+import { PaddingDirection } from "./enums";
 import { Model, WordPiece, WordPieceOptions } from "./models";
 import { whitespacePreTokenizer } from "./pre-tokenizers";
 import { RawEncoding } from "./raw-encoding";
@@ -137,4 +138,31 @@ describe("RawEncoding", () => {
       expect(index).toBeUndefined();
     });
   });
+
+  describe("pad", () => {
+    it("works correctly with only one parameter", () => {
+      encoding.pad(10);
+      expect(encoding.getTokens()).toHaveLength(10);
+    });
+
+    it("accepts `undefined` as second parameter", () => {
+      encoding.pad(10, undefined);
+      expect(encoding.getTokens()).toHaveLength(10);
+    });
+
+    it("accepts options as second parameter", () => {
+      encoding.pad(10, {
+        direction: PaddingDirection.Left,
+        padToken: "[PA]",
+        padTypeId: 10,
+        padId: 400
+      });
+
+      const tokens = encoding.getTokens();
+      expect(tokens).toHaveLength(10);
+      expect(tokens[0]).toBe("[PA]");
+      expect(encoding.getTypeIds()[0]).toBe(10);
+      expect(encoding.getIds()[0]).toBe(400);
+    });
+  });
 });

bindings/node/native/src/encoding.rs

@@ -257,7 +257,7 @@ declare_types! {
             //   padToken?: string = "[PAD]"
             // }
             let length = cx.extract::<usize>(0)?;
-            let params = cx.extract_opt::<PaddingParams>(0)?
+            let params = cx.extract_opt::<PaddingParams>(1)?
                 .map_or_else(tk::PaddingParams::default, |p| p.0);
 
             let mut this = cx.this();