feat(util-dynamodb): add option for using native array over sets

packages/util-dynamodb/src/convertToNative.spec.ts

@@ -242,18 +242,38 @@ describe("convertToNative", () => {
           new Set(input.map((numString) => ({ value: numString })))
         );
       });
+
+      it("with options.preferNativeArrays=true", () => {
+        expect(convertToNative({ NS: input }, { preferNativeArrays: true })).toEqual([1, 2, BigInt(9007199254740996)]);
+      });
     });
 
-    it("binary set", () => {
-      const uint8Arr1 = new Uint8Array([...Array(4).keys()]);
-      const uint8Arr2 = new Uint8Array([...Array(2).keys()]);
-      const input = [uint8Arr1, uint8Arr2];
-      expect(convertToNative({ BS: input })).toEqual(new Set(input));
+    describe("binary set", () => {
+      it("without options.preferNativeArrays", () => {
+        const uint8Arr1 = new Uint8Array([...Array(4).keys()]);
+        const uint8Arr2 = new Uint8Array([...Array(2).keys()]);
+        const input = [uint8Arr1, uint8Arr2];
+        expect(convertToNative({ BS: input })).toEqual(new Set(input));
+      });
+
+      it("with options.preferNativeArrays=true", () => {
+        const uint8Arr1 = new Uint8Array([...Array(4).keys()]);
+        const uint8Arr2 = new Uint8Array([...Array(2).keys()]);
+        const input = [uint8Arr1, uint8Arr2];
+        expect(convertToNative({ BS: input }, { preferNativeArrays: true })).toEqual(input);
+      });
     });
 
-    it("string set", () => {
-      const input = ["one", "two", "three"];
-      expect(convertToNative({ SS: input })).toEqual(new Set(input));
+    describe("string set", () => {
+      it("without options.preferNativeArrays", () => {
+        const input = ["one", "two", "three"];
+        expect(convertToNative({ SS: input })).toEqual(new Set(input));
+      });
+
+      it("with options.preferNativeArrays=true", () => {
+        const input = ["one", "two", "three"];
+        expect(convertToNative({ SS: input }, { preferNativeArrays: true })).toEqual(input);
+      });
     });
   });
 

packages/util-dynamodb/src/convertToNative.ts

@@ -29,10 +29,19 @@ export const convertToNative = (data: AttributeValue, options?: unmarshallOption
         case "M":
           return convertMap(value as Record<string, AttributeValue>, options);
         case "NS":
+          if (options?.preferNativeArrays) {
+            return (value as string[]).map((item) => convertNumber(item, options));
+          }
           return new Set((value as string[]).map((item) => convertNumber(item, options)));
         case "BS":
+          if (options?.preferNativeArrays) {
+            return (value as Uint8Array[]).map(convertBinary);
+          }
           return new Set((value as Uint8Array[]).map(convertBinary));
         case "SS":
+          if (options?.preferNativeArrays) {
+            return (value as string[]).map(convertString);
+          }
           return new Set((value as string[]).map(convertString));
         default:
           throw new Error(`Unsupported type passed: ${key}`);

packages/util-dynamodb/src/unmarshall.ts

@@ -20,6 +20,11 @@ export interface unmarshallOptions {
    * but false if directly using the unmarshall function (backwards compatibility).
    */
   convertWithoutMapWrapper?: boolean;
+
+  /**
+   * When true, return native JavaScript arrays instead of Sets.
+   */
+  preferNativeArrays?: boolean;
 }
 
 /**