Added util function getSovereignAccountAddresses (#226)

.changeset/tender-apes-build.md

@@ -0,0 +1,5 @@
+---
+'@moonbeam-network/xcm-utils': patch
+---
+
+Added util function getSovereignAccountAddresses

packages/utils/package.json

@@ -59,6 +59,7 @@
   },
   "peerDependencies": {
     "@polkadot/api": "^10.10.1",
-    "@polkadot/apps-config": "^0.132.1"
+    "@polkadot/apps-config": "^0.132.1",
+    "@polkadot/util": "^12.5.1"
   }
 }

packages/utils/src/polkadot/index.ts

@@ -1 +1,2 @@
 export * from './polkadot.api';
+export * from './polkadot.address';

packages/utils/src/polkadot/polkadot.address.test.ts

@@ -0,0 +1,25 @@
+import { getSovereignAccountAddresses } from './polkadot.address';
+
+describe('utils - polkadot address', () => {
+  describe('getSovereignAccountAddresses', () => {
+    it('should get correct addresses for paraId 1000', async () => {
+      expect(getSovereignAccountAddresses(1000)).toStrictEqual({
+        generic:
+          '0x7369626ce8030000000000000000000000000000000000000000000000000000',
+        moonbeam: '0x7369626ce8030000000000000000000000000000',
+        relay:
+          '0x70617261e8030000000000000000000000000000000000000000000000000000',
+      });
+    });
+
+    it('should get correct addresses for paraId 3019', async () => {
+      expect(getSovereignAccountAddresses(3019)).toStrictEqual({
+        generic:
+          '0x7369626ccb0b0000000000000000000000000000000000000000000000000000',
+        moonbeam: '0x7369626ccb0b0000000000000000000000000000',
+        relay:
+          '0x70617261cb0b0000000000000000000000000000000000000000000000000000',
+      });
+    });
+  });
+});

packages/utils/src/polkadot/polkadot.address.ts

@@ -0,0 +1,18 @@
+import { bnToU8a, u8aToHex, stringToU8a } from '@polkadot/util';
+
+export function getSovereignAccountAddresses(paraId: number) {
+  const paraIdU8a = bnToU8a(paraId, { bitLength: 32 });
+  const relay = u8aToHex(
+    new Uint8Array([...stringToU8a('para'), ...paraIdU8a]),
+  ).padEnd(66, '0');
+  const generic = u8aToHex(
+    new Uint8Array([...stringToU8a('sibl'), ...paraIdU8a]),
+  ).padEnd(66, '0');
+  const moonbeam = generic.slice(0, 42);
+
+  return {
+    generic,
+    moonbeam,
+    relay,
+  };
+}