added asNativeToken fn

bindings/nodejs/lib/types/block/output/feature.ts

@@ -137,6 +137,16 @@ class NativeTokenFeature extends Feature {
         this.id = nativeToken.id;
         this.amount = nativeToken.amount;
     }
+
+    /**
+     * Returns the native token contained in this feature.
+     */
+    public asNativeToken(): INativeToken {
+        return {
+            id: this.id,
+            amount: this.amount,
+        };
+    }
 }
 
 /**

bindings/nodejs/lib/types/block/output/output.ts

@@ -13,6 +13,7 @@ import { HexEncodedString, NumericString, u64 } from '../../utils';
 import { TokenScheme, TokenSchemeDiscriminator } from './token-scheme';
 import { AccountId, NftId, AnchorId, DelegationId } from '../id';
 import { EpochIndex } from '../../block/slot';
+import { INativeToken } from '../../models/native-token';
 
 export type OutputId = HexEncodedString;
 
@@ -126,14 +127,14 @@ abstract class CommonOutput extends Output {
     /**
      * The native token held by the output.
      */
-    getNativeToken(): NativeTokenFeature | undefined {
+    getNativeToken(): INativeToken | undefined {
         if (!this.features) {
             return undefined;
         }
 
         for (const feature of this.features) {
             if (feature instanceof NativeTokenFeature) {
-                return feature as NativeTokenFeature;
+                return (feature as NativeTokenFeature).asNativeToken();
             }
         }
         return undefined;