feat: get the portfolio custodian

src/api/entities/Portfolio/__tests__/index.ts

@@ -166,4 +166,44 @@ describe('Portfolio class', () => {
       expect(result[1].locked).toEqual(new BigNumber(0));
     });
   });
+
+  describe('method: getCustodian', () => {
+    let did: string;
+    let id: BigNumber;
+
+    beforeAll(() => {
+      did = 'someDid';
+      id = new BigNumber(1);
+      sinon.stub(utilsModule, 'portfolioIdToMeshPortfolioId');
+    });
+
+    afterAll(() => {
+      sinon.restore();
+    });
+
+    test('should return the custodian of the portfolio', async () => {
+      const custodianDid = 'custodianDid';
+      const identityIdToStringStub = sinon.stub(utilsModule, 'identityIdToString');
+
+      dsMockUtils
+        .createQueryStub('portfolio', 'portfolioCustodian')
+        .returns(dsMockUtils.createMockOption(dsMockUtils.createMockIdentityId(custodianDid)));
+
+      identityIdToStringStub.returns(custodianDid);
+
+      let portfolio = new Portfolio({ did, id }, context);
+      let result = await portfolio.getCustodian();
+
+      expect(result.did).toEqual(custodianDid);
+
+      dsMockUtils.createQueryStub('portfolio', 'portfolioCustodian').returns({});
+
+      identityIdToStringStub.returns(did);
+
+      portfolio = new Portfolio({ did, id }, context);
+      result = await portfolio.getCustodian();
+
+      expect(result.did).toEqual(did);
+    });
+  });
 });

src/api/entities/Portfolio/index.ts

@@ -4,7 +4,12 @@ import { Ticker } from 'polymesh-types/types';
 
 import { Entity, Identity, SecurityToken } from '~/api/entities';
 import { Context } from '~/base';
-import { balanceToBigNumber, portfolioIdToMeshPortfolioId, tickerToString } from '~/utils';
+import {
+  balanceToBigNumber,
+  identityIdToString,
+  portfolioIdToMeshPortfolioId,
+  tickerToString,
+} from '~/utils';
 
 import { PortfolioBalance } from './types';
 
@@ -130,4 +135,33 @@ export class Portfolio extends Entity<UniqueIdentifiers> {
 
     return values(assetBalances);
   }
+
+  /**
+   * Retrieve the custodian of this portfolio
+   */
+  public async getCustodian(): Promise<Identity> {
+    const {
+      owner: { did },
+      _id,
+      context: {
+        polymeshApi: {
+          query: { portfolio },
+        },
+      },
+      context,
+    } = this;
+
+    const rawPortfolioId = portfolioIdToMeshPortfolioId({ did, number: _id }, context);
+    const portfolioCustodian = await portfolio.portfolioCustodian(rawPortfolioId);
+
+    let custodianDid;
+    try {
+      const rawIdentityId = portfolioCustodian.unwrap();
+      custodianDid = identityIdToString(rawIdentityId);
+    } catch (_) {
+      custodianDid = did;
+    }
+
+    return new Identity({ did: custodianDid }, context);
+  }
 }