feat: add AlchemyProvider class

src/providers/AlchemyProvider.ts

@@ -0,0 +1,37 @@
+import { BaseProvider } from './BaseProvider';
+
+export class AlchemyProvider extends BaseProvider {
+  /**
+   * @ignore
+   */
+  selectRpcUrl(): string {
+    return this._rpcUrls[0];
+  }
+
+  /**
+   * @ignore
+   */
+  post(body: Record<string, unknown>): Promise<any> {
+    return this._post(body);
+  }
+
+  /**
+   * @param apiKey The Alchemy API key
+   * @param network The Ethereum network to connect to
+   */
+  constructor(apiKey: string, network = 'mainnet') {
+    const alchemyUrl = `https://eth-${network}.alchemyapi.io/v2/${apiKey}`;
+    super([alchemyUrl]);
+  }
+}
+
+/**
+ * Helper function to avoid "new"
+ *
+ * @param apiKey the Alchemy API key
+ * @param network the Ethereum network to connect to
+ * @returns an initiated {@link AlchemyProvider}
+ */
+export function alchemyProvider(apiKey: string, network?: string) {
+  return new AlchemyProvider(apiKey, network);
+}