feat: get the treasury balance

src/Polymesh.ts

@@ -5,6 +5,7 @@ import { ApolloClient, ApolloQueryResult } from 'apollo-client';
 import { ApolloLink } from 'apollo-link';
 import { setContext } from 'apollo-link-context';
 import { HttpLink } from 'apollo-link-http';
+import BigNumber from 'bignumber.js';
 import { polymesh } from 'polymesh-types/definitions';
 
 import { Identity, SecurityToken, TickerReservation } from '~/api/entities';
@@ -640,6 +641,31 @@ export class Polymesh {
     };
   }
 
+  /**
+   * Get the Treasury POLYX balance
+   *
+   * @note can be subscribed to
+   */
+  public getTreasuryBalance(): Promise<BigNumber>;
+  public getTreasuryBalance(callback: SubCallback<BigNumber>): Promise<UnsubCallback>;
+
+  // eslint-disable-next-line require-jsdoc
+  public async getTreasuryBalance(
+    callback?: SubCallback<BigNumber>
+  ): Promise<BigNumber | UnsubCallback> {
+    const accountId = this.getTreasury();
+
+    if (callback) {
+      return this.context.accountBalance(accountId, ({ free }) => {
+        // eslint-disable-next-line standard/no-callback-literal
+        callback(free);
+      });
+    }
+
+    const { free } = await this.getAccountBalance({ accountId });
+    return free;
+  }
+
   // TODO @monitz87: remove when the dApp team no longer needs it
   /* istanbul ignore next: only for testing purposes */
   /**

src/__tests__/Polymesh.ts

@@ -1025,6 +1025,48 @@ describe('Polymesh Class', () => {
     });
   });
 
+  describe.only('method: getTreasuryBalance', () => {
+    let fakeBalance: AccountBalance;
+
+    beforeAll(() => {
+      fakeBalance = {
+        free: new BigNumber(500000),
+        locked: new BigNumber(0),
+      };
+      dsMockUtils.configureMocks({ contextOptions: { balance: fakeBalance } });
+    });
+
+    test('should return the POLYX balance of the treasury account', async () => {
+      const polymesh = await Polymesh.connect({
+        nodeUrl: 'wss://some.url',
+      });
+
+      const result = await polymesh.getTreasuryBalance();
+      expect(result).toEqual(fakeBalance.free);
+    });
+
+    test.only('should allow subscription', async () => {
+      const unsubCallback = 'unsubCallback';
+
+      const accountBalanceStub = dsMockUtils
+        .getContextInstance()
+        .accountBalance.resolves(unsubCallback);
+
+      const polymesh = await Polymesh.connect({
+        nodeUrl: 'wss://some.url',
+      });
+
+      const callback = (() => 1 as unknown) as SubCallback<BigNumber>;
+      const result = await polymesh.getTreasuryBalance(callback);
+      expect(result).toEqual(unsubCallback);
+      sinon.assert.calledWithExactly(
+        accountBalanceStub,
+        '5EYCAe5ijAx5xEfZdpCna3grUpY1M9M5vLUH5vpmwV1EnaYR',
+        callback
+      );
+    });
+  });
+
   describe('method: onConnectionError', () => {
     test('should call the supplied listener when the event is emitted and return an unsubscribe callback', async () => {
       const polkadot = dsMockUtils.getApiInstance();