Inject custom derives (#711)

packages/api-derive/src/index.spec.ts

@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-import { Observable } from 'rxjs';
+import { Observable, from } from 'rxjs';
 import ApiRx from '@polkadot/api/rx';
 import { ApiInterface$Rx } from '@polkadot/api/types';
 import MockProvider from '@polkadot/rpc-provider/mock';
@@ -34,31 +34,62 @@ const testFunction = (api: ApiInterface$Rx) => {
 };
 
 describe('derive', () => {
-  const api = new ApiRx(new MockProvider());
+  describe('builtin', () => {
+    const api = new ApiRx(new MockProvider());
 
-  beforeAll((done) => api.isReady.subscribe(() => done()));
+    beforeAll((done) => {
+      api.isReady.subscribe(() => done());
+    });
 
-  testFunction(api)('accounts', 'idAndIndex', []);
-  testFunction(api)('accounts', 'idToIndex', []);
-  testFunction(api)('accounts', 'indexes', []);
-  testFunction(api)('accounts', 'indexToId', []);
+    testFunction(api)('accounts', 'idAndIndex', []);
+    testFunction(api)('accounts', 'idToIndex', []);
+    testFunction(api)('accounts', 'indexes', []);
+    testFunction(api)('accounts', 'indexToId', []);
 
-  testFunction(api)('balances', 'fees', []);
-  testFunction(api)('balances', 'validatingBalance', []);
-  testFunction(api)('balances', 'validatingBalances', []);
-  testFunction(api)('balances', 'votingBalance', []);
-  testFunction(api)('balances', 'votingBalances', []);
-  testFunction(api)('balances', 'votingBalancesNominatorsFor', []);
+    testFunction(api)('balances', 'fees', []);
+    testFunction(api)('balances', 'validatingBalance', []);
+    testFunction(api)('balances', 'validatingBalances', []);
+    testFunction(api)('balances', 'votingBalance', []);
+    testFunction(api)('balances', 'votingBalances', []);
+    testFunction(api)('balances', 'votingBalancesNominatorsFor', []);
 
-  testFunction(api)('chain', 'bestNumber', []);
-  testFunction(api)('chain', 'bestNumberFinalised', []);
+    testFunction(api)('chain', 'bestNumber', []);
+    testFunction(api)('chain', 'bestNumberFinalised', []);
 
-  testFunction(api)('democracy', 'referendumInfos', []);
-  testFunction(api)('democracy', 'referendums', []);
-  testFunction(api)('democracy', 'referendumVotesFor', []);
-  testFunction(api)('democracy', 'votes', []);
+    testFunction(api)('democracy', 'referendumInfos', []);
+    testFunction(api)('democracy', 'referendums', []);
+    testFunction(api)('democracy', 'referendumVotesFor', []);
+    testFunction(api)('democracy', 'votes', []);
 
-  testFunction(api)('session', 'eraLength', []);
-  testFunction(api)('session', 'eraProgress', []);
-  testFunction(api)('session', 'sessionProgress', []);
+    testFunction(api)('session', 'eraLength', []);
+    testFunction(api)('session', 'eraProgress', []);
+    testFunction(api)('session', 'sessionProgress', []);
+  });
+
+  describe('custom', () => {
+    const api = new ApiRx({
+      derives: {
+        balances: {
+          fees: () => () => from(['a', 'b'])
+        },
+        custom: {
+          test: () => () => from([1, 2, 3])
+        }
+      },
+      provider: new MockProvider()
+    });
+
+    beforeAll((done) => {
+      api.isReady.subscribe(() => done());
+    });
+
+    // override
+    testFunction(api)('balances', 'fees', ['a', 'b']);
+
+    // new
+    testFunction(api)('custom' as any, 'test', [1, 2, 3]);
+
+    // existing
+    testFunction(api)('chain', 'bestNumber', []);
+  });
 });

packages/api-derive/src/index.ts

@@ -2,15 +2,16 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
+import { Observable } from 'rxjs';
 import { ApiInterface$Rx } from '@polkadot/api/types';
 
+import { cache } from './util/cache';
 import * as accounts from './accounts';
 import * as balances from './balances';
 import * as chain from './chain';
 import * as democracy from './democracy';
 import * as session from './session';
 import * as staking from './staking';
-import { cache } from './util/cache';
 
 // Put all derived functions in an object, for easier Object.keys()-ing.
 const functions = { accounts, balances, chain, democracy, session, staking };
@@ -23,6 +24,16 @@ type ReturnTypes<T extends Record<keyof T, (...args: any[]) => any>> = {
   [P in keyof T]: ReturnType<T[P]>
 };
 
+export interface DeriveCustomMethod {
+  (api: ApiInterface$Rx): (...args: Array<any>) => Observable<any>;
+}
+
+export interface DeriveCustom {
+  [index: string]: {
+    [index: string]: DeriveCustomMethod
+  };
+}
+
 export interface Derive {
   accounts: ReturnTypes<typeof accounts>;
   balances: ReturnTypes<typeof balances>;
@@ -32,22 +43,30 @@ export interface Derive {
   staking: ReturnTypes<typeof staking>;
 }
 
-export default function decorateDerive (api: ApiInterface$Rx): Derive {
-  const derive = {} as Derive;
-
+function injectFunctions (api: ApiInterface$Rx, derive: Derive, functions: DeriveCustom): Derive {
   Object.keys(functions).forEach((sectionName: string) => {
     const section = functions[sectionName as keyof Derive];
-    derive[sectionName as keyof Derive] = Object.keys(section).reduce((result, methodName) => {
+    const result = derive[sectionName as keyof Derive] = derive[sectionName as keyof Derive] || {};
+
+    Object.keys(section).forEach((methodName) => {
       // Create cache for the section_method function
       // @ts-ignore No idea how to make this work...
       const cached = cache(section[methodName as keyof section]);
+
       // Add this cached function into the result
       // @ts-ignore No idea how to make this work...
       result[methodName as keyof section] = cached(api);
-
-      return result;
-    }, {} as ReturnTypes<typeof section>);
+    });
   });
 
   return derive;
 }
+
+export default function decorateDerive (api: ApiInterface$Rx, custom: DeriveCustom = {}): Derive {
+  const derive = {} as Derive;
+
+  injectFunctions(api, derive, functions);
+  injectFunctions(api, derive, custom);
+
+  return derive;
+}