Add spend bundle aggregation

Author: Rigidity

package.json

@@ -1,7 +1,7 @@
 {
     "name": "@rigidity/chia",
     "author": "rigidity",
-    "version": "1.6.1",
+    "version": "1.7.0",
     "description": "Chia RPC client and various helper utilities.",
     "repository": "https://github.com/Rigidity/chia.git",
     "main": "dist/index.js",

src/utils/spend.ts

@@ -0,0 +1,17 @@
+import { AugSchemeMPL, JacobianPoint } from '@rigidity/bls-signatures';
+import { SpendBundle } from '../types/SpendBundle';
+
+export function aggregateSpendBundles(
+    spendBundles: SpendBundle[]
+): SpendBundle {
+    return {
+        coin_spends: spendBundles
+            .map((spendBundle) => spendBundle.coin_spends)
+            .flat(),
+        aggregated_signature: AugSchemeMPL.aggregate(
+            spendBundles.map((spendBundle) =>
+                JacobianPoint.fromHexG2(spendBundle.aggregated_signature)
+            )
+        ).toHex(),
+    };
+}