Implementation of the RPC using JavaScript proxies

Author: steveluscher

packages/rpc-core/src/__tests__/rpc-test.ts

@@ -0,0 +1,26 @@
+import { IJsonRpcTransport } from '@solana/rpc-transport';
+import { rpc } from '../rpc';
+
+describe('rpc', () => {
+    let transport: jest.Mocked<IJsonRpcTransport>;
+    beforeEach(() => {
+        transport = { send: jest.fn() };
+    });
+    describe('a method call without params', () => {
+        beforeEach(async () => {
+            await rpc.getBlockHeight(transport);
+        });
+        it('calls `send` on the supplied transport with the function name as the method name and `undefined` params', () => {
+            expect(transport.send).toHaveBeenCalledWith('getBlockHeight', undefined);
+        });
+    });
+    describe('a method call with params', () => {
+        const params = [1, undefined, { commitment: 'finalized' }] as const;
+        beforeEach(async () => {
+            await rpc.getBlocks(transport, ...params);
+        });
+        it('calls `send` on the supplied transport with the function name as the method name and the supplied params', () => {
+            expect(transport.send).toHaveBeenCalledWith('getBlocks', params);
+        });
+    });
+});

packages/rpc-core/src/index.ts

@@ -0,0 +1 @@
+export * from './rpc';

packages/rpc-core/src/rpc.ts

@@ -0,0 +1,22 @@
+import { IJsonRpcTransport } from '@solana/rpc-transport';
+import { JsonRpcApi } from './types/jsonRpcApi';
+
+export const rpc = /* #__PURE__ */ new Proxy<JsonRpcApi>({} as JsonRpcApi, {
+    defineProperty() {
+        return false;
+    },
+    deleteProperty() {
+        return false;
+    },
+    get<TMethodName extends keyof JsonRpcApi>(target: JsonRpcApi, p: TMethodName) {
+        if (target[p] == null) {
+            const method = p.toString();
+            target[p] = async function (transport: IJsonRpcTransport, ...params: Parameters<JsonRpcApi[TMethodName]>) {
+                const normalizedParams = params.length ? params : undefined;
+                const result = await transport.send(method, normalizedParams);
+                return result;
+            } as unknown as JsonRpcApi[TMethodName];
+        }
+        return target[p];
+    },
+});