Merge pull request #2 from golemcloud/sync-fetch-support

Add synchronous fetch support functions

src/eventloop.ts

@@ -0,0 +1,65 @@
+// Copyright 2024 Golem Cloud
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { Result } from "./result";
+
+/**
+ * Workaround helper until async support arrives: runEventLoopUntilInterest keeps
+ * running the event loop until all pending async tasks and jobs (e.g. Fetch promises)
+ * are finished.
+ */
+export declare const runEventLoopUntilInterest: () => void;
+
+/**
+ * Waits for a promise (by using runEventLoopUntilInterest) and returns
+ * its result synchronously. In case of rejection it rethrows the error.
+ * @param promise
+ */
+export function asyncToSync<T>(promise: Promise<T>): T {
+   let success = false;
+   let done = false;
+   let result: T;
+   let error: any;
+
+   promise
+      .then((r) => {
+         result = r;
+         success = true;
+         done = true;
+      })
+      .catch((e) => {
+         error = e;
+         done = true;
+      });
+
+   runEventLoopUntilInterest();
+
+   if (!done) {
+      throw new Error("asyncToSync: illegal state: not done");
+   }
+
+   if (!success) {
+      throw error;
+   }
+
+   return result;
+}
+
+/**
+ * Result returning variant of asyncToSync;
+ * @param promise
+ */
+export function asyncToSyncAsResult<T>(promise: Promise<T>): Result<T, any> {
+   return Result.tryCatch(() => asyncToSync(promise));
+}

src/fetch.ts

@@ -0,0 +1,34 @@
+// Copyright 2024 Golem Cloud
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { asyncToSync, asyncToSyncAsResult } from "./eventloop";
+import type { Result } from "./result";
+
+/**
+ * Synchronous wrapper of fetch
+ * @param input
+ * @param init
+ */
+function fetchSync(input: RequestInfo | URL, init?: RequestInit): Response {
+   return asyncToSync(fetch(input, init));
+}
+
+/**
+ * Result returning variant of fetchSync
+ * @param input
+ * @param init
+ */
+function fetchSyncAsResult(input: RequestInfo | URL, init?: RequestInit): Result<Response, any> {
+   return asyncToSyncAsResult(fetch(input, init));
+}

src/index.ts

@@ -13,6 +13,8 @@
 // limitations under the License.
 
 export * from "./bindgen/bindgen";
+export * from "./eventloop";
+export * from "./fetch";
 export * from "./guard";
 export * from "./result";
 export * from "./transaction";