feat(experimental): add rootNotifications websocket method (#1646)

* fix: broken timestamp test

* refactor(experimental): change u64 types to slot in slot notifications

* feat(experimental): add `slotsUpdatesNotifications` websocket method

* feat(experimental): add `slotsUpdatesNotifications` websocket method

* feat(experimental): add `rootNotifications` websocket method

packages/rpc-core/src/rpc-subscriptions/__tests__/root-notifications-test.ts

@@ -0,0 +1,4 @@
+describe('rootNotifications', () => {
+    // TODO: A change in root takes too long to occur in order for our tests to pass.
+    it.todo('produces root notifications');
+});

packages/rpc-core/src/rpc-subscriptions/__typetests__/root-notifications-type-test.ts

@@ -0,0 +1,19 @@
+/* eslint-disable @typescript-eslint/ban-ts-comment */
+
+import { PendingRpcSubscription, RpcSubscriptions } from '@solana/rpc-transport/dist/types/json-rpc-types';
+
+import { Slot } from '../../rpc-methods/common';
+import { RootNotificationsApi } from '../root-notifications';
+
+async () => {
+    const rpcSubscriptions = null as unknown as RpcSubscriptions<RootNotificationsApi>;
+
+    type TNotification = Slot;
+    rpcSubscriptions.rootNotifications() satisfies PendingRpcSubscription<TNotification>;
+    rpcSubscriptions.rootNotifications().subscribe({ abortSignal: new AbortController().signal }) satisfies Promise<
+        AsyncIterable<TNotification>
+    >;
+
+    // @ts-expect-error Takes no params.
+    rpcSubscriptions.rootNotifications({ commitment: 'finalized' });
+};

packages/rpc-core/src/rpc-subscriptions/index.ts

@@ -2,14 +2,15 @@ import { IRpcSubscriptionsApi, RpcSubscription } from '@solana/rpc-transport/dis
 
 import { patchParamsForSolanaLabsRpc } from '../params-patcher';
 import { patchResponseForSolanaLabsRpcSubscriptions } from '../response-patcher';
+import { RootNotificationsApi } from './root-notifications';
 import { SlotNotificationsApi } from './slot-notifications';
 import { SlotsUpdatesNotificationsApi } from './slots-updates-notifications';
 
 type Config = Readonly<{
     onIntegerOverflow?: (methodName: string, keyPath: (number | string)[], value: bigint) => void;
 }>;
 
-export type SolanaRpcSubscriptions = SlotNotificationsApi;
+export type SolanaRpcSubscriptions = RootNotificationsApi & SlotNotificationsApi;
 export type SolanaRpcSubscriptionsUnstable = SlotsUpdatesNotificationsApi;
 
 export function createSolanaRpcSubscriptionsApi(

packages/rpc-core/src/rpc-subscriptions/root-notifications.ts

@@ -0,0 +1,13 @@
+import { Slot } from '../rpc-methods/common';
+
+type RootNotificationsApiNotification = Slot;
+
+export interface RootNotificationsApi {
+    /**
+     * Subscribe to receive notification anytime a new root is set by the validator
+     */
+    rootNotifications(
+        // FIXME: https://github.com/solana-labs/solana-web3.js/issues/1389
+        NO_CONFIG?: Record<string, never>
+    ): RootNotificationsApiNotification;
+}