feat: top-level-for-await (#3212)

.prettierignore

@@ -1,5 +1,6 @@
 cli/tests/error_syntax.js
 cli/tests/badly_formatted.js
+cli/tests/top_level_for_await.js
 std/**/testdata
 std/**/vendor
 std/node_modules

cli/js/compiler.ts

@@ -616,6 +616,9 @@ window.compilerMain = function compilerMain(): void {
 
       diagnostics = ts.getPreEmitDiagnostics(program).filter(
         ({ code }): boolean => {
+          // TS1103: 'for-await-of' statement is only allowed within an async
+          // function or async generator.
+          if (code === 1103) return false;
           // TS1308: 'await' expression is only allowed within an async
           // function.
           if (code === 1308) return false;

cli/tests/045_proxy_client.ts

@@ -1,7 +1,3 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-async function main(): Promise<void> {
 const res = await fetch("http://localhost:4545/std/examples/colors.ts");
 console.log(`Response http: ${await res.text()}`);
-}
-
-main();

cli/tests/045_proxy_test.ts

@@ -55,11 +55,7 @@ async function testModuleDownload(): Promise<void> {
   http.close();
 }
 
-async function main(): Promise<void> {
 proxyServer();
 await testFetch();
 await testModuleDownload();
 Deno.exit(0);
-}
-
-main();

cli/tests/integration_tests.rs

@@ -597,3 +597,13 @@ itest!(top_level_await_ts {
   args: "--allow-read top_level_await.ts",
   output: "top_level_await.out",
 });
+
+itest!(top_level_for_await {
+  args: "top_level_for_await.js",
+  output: "top_level_for_await.out",
+});
+
+itest!(top_level_for_await_ts {
+  args: "top_level_for_await.ts",
+  output: "top_level_for_await.out",
+});

cli/tests/top_level_for_await.js

@@ -0,0 +1,10 @@
+async function* asyncGenerator() {
+  let i = 0;
+  while (i < 3) {
+    yield i++;
+  }
+}
+
+for await (const num of asyncGenerator()) {
+  console.log(num);
+};

cli/tests/top_level_for_await.out

@@ -0,0 +1,3 @@
+0
+1
+2

cli/tests/top_level_for_await.ts

@@ -0,0 +1,10 @@
+async function* asyncGenerator(): AsyncIterableIterator<number> {
+  let i = 0;
+  while (i < 3) {
+    yield i++;
+  }
+}
+
+for await (const num of asyncGenerator()) {
+  console.log(num);
+}

std/examples/cat.ts

@@ -1,10 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-async function cat(filenames: string[]): Promise<void> {
+const filenames = Deno.args.slice(1);
 for (const filename of filenames) {
   const file = await Deno.open(filename);
   await Deno.copy(Deno.stdout, file);
   file.close();
 }
-}
-
-cat(Deno.args.slice(1));

std/examples/catj.ts

@@ -79,7 +79,6 @@ function print(data: any): void {
   }
 }
 
-async function main(): Promise<void> {
 const parsedArgs = parse(Deno.args.slice(1));
 
 if (parsedArgs.h || parsedArgs.help || parsedArgs._.length === 0) {
@@ -105,6 +104,3 @@ async function main(): Promise<void> {
     print(json);
   }
 }
-}
-
-main();

std/examples/curl.ts

@@ -1,8 +1,4 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-async function curl(url: string): Promise<void> {
+const url = Deno.args[1];
 const res = await fetch(url);
 await Deno.copy(Deno.stdout, res.body);
-}
-
-await curl(Deno.args[1]);
-Deno.exit(0);

std/http/README.md

@@ -56,14 +56,11 @@ console.log("Set-Cookie:", cookieHeader);
 ```typescript
 import { serve } from "https://deno.land/std/http/server.ts";
 const s = serve("0.0.0.0:8000");
+const body = new TextEncoder().encode("Hello World\n");
 
-async function main() {
 for await (const req of s) {
-    req.respond({ body: new TextEncoder().encode("Hello World\n") });
+  req.respond({ body });
 }
-}
-
-main();
 ```
 
 ### File Server

std/http/testdata/simple_server.ts

@@ -2,10 +2,8 @@
 // This is an example of a server that responds with an empty body
 import { serve } from "../server.ts";
 
-window.onload = async function main() {
 const addr = "0.0.0.0:4502";
 console.log(`Simple server listening on ${addr}`);
 for await (const req of serve(addr)) {
   req.respond({});
 }
-}

std/manual.md

@@ -937,12 +937,10 @@ Example:
 
 import { serve } from "http/server.ts";
 
-window.onload = async function() {
 const body = new TextEncoder().encode("Hello World\n");
 for await (const req of serve(":8000")) {
   req.respond({ body });
 }
-};
 ```
 
 ```shell

std/ws/README.md

@@ -15,8 +15,8 @@ import {
   WebSocket
 } from "https://deno.land/std/ws/mod.ts";
 
+/** websocket echo server */
 const port = Deno.args[1] || "8080";
-async function main(): Promise<void> {
 console.log(`websocket server is running on :${port}`);
 for await (const req of serve(`:${port}`)) {
   const { headers, conn } = req;
@@ -66,11 +66,6 @@ async function main(): Promise<void> {
       }
     );
 }
-}
-
-if (import.meta.main) {
-  main();
-}
 ```
 
 ### Client
@@ -88,7 +83,7 @@ import { TextProtoReader } from "https://deno.land/std/textproto/mod.ts";
 import { blue, green, red, yellow } from "https://deno.land/std/fmt/colors.ts";
 
 const endpoint = Deno.args[1] || "ws://127.0.0.1:8080";
-async function main(): Promise<void> {
+/** simple websocket cli */
 const sock = await connectWebSocket(endpoint);
 console.log(green("ws connected! (type 'close' to quit)"));
 (async function(): Promise<void> {
@@ -104,6 +99,7 @@ async function main(): Promise<void> {
     }
   }
 })();
+
 const tpr = new TextProtoReader(new BufReader(Deno.stdin));
 while (true) {
   await Deno.stdout.write(encode("> "));
@@ -119,15 +115,17 @@ async function main(): Promise<void> {
   } else {
     await sock.send(line);
   }
-    await new Promise((resolve): number => setTimeout(resolve, 0));
+  // FIXME: Without this,
+  // sock.receive() won't resolved though it is readable...
+  await new Promise(
+    (resolve): void => {
+      setTimeout(resolve, 0);
+    }
+  );
 }
 await sock.close(1000);
+// FIXME: conn.close() won't shutdown process...
 Deno.exit(0);
-}
-
-if (import.meta.main) {
-  main();
-}
 ```
 
 ## API

std/ws/example_client.ts

@@ -11,7 +11,6 @@ import { blue, green, red, yellow } from "../fmt/colors.ts";
 
 const endpoint = Deno.args[1] || "ws://127.0.0.1:8080";
 /** simple websocket cli */
-async function main(): Promise<void> {
 const sock = await connectWebSocket(endpoint);
 console.log(green("ws connected! (type 'close' to quit)"));
 (async function(): Promise<void> {
@@ -27,6 +26,7 @@ async function main(): Promise<void> {
     }
   }
 })();
+
 const tpr = new TextProtoReader(new BufReader(Deno.stdin));
 while (true) {
   await Deno.stdout.write(encode("> "));
@@ -53,8 +53,3 @@ async function main(): Promise<void> {
 await sock.close(1000);
 // FIXME: conn.close() won't shutdown process...
 Deno.exit(0);
-}
-
-if (import.meta.main) {
-  main();
-}

std/ws/example_server.ts

@@ -9,7 +9,6 @@ import {
 
 /** websocket echo server */
 const port = Deno.args[1] || "8080";
-async function main(): Promise<void> {
 console.log(`websocket server is running on :${port}`);
 for await (const req of serve(`:${port}`)) {
   const { headers, conn } = req;
@@ -59,8 +58,3 @@ async function main(): Promise<void> {
       }
     );
 }
-}
-
-if (import.meta.main) {
-  main();
-}

tools/deno_http_proxy.ts

@@ -5,13 +5,6 @@ const addr = Deno.args[1] || "127.0.0.1:4500";
 const originAddr = Deno.args[2] || "127.0.0.1:4501";
 const server = serve(addr);
 
-async function main(): Promise<void> {
-  console.log(`Proxy listening on http://${addr}/`);
-  for await (const req of server) {
-    proxyRequest(req);
-  }
-}
-
 async function proxyRequest(req: ServerRequest): Promise<void> {
   const url = `http://${originAddr}${req.url}`;
   const resp = await fetch(url, {
@@ -21,4 +14,7 @@ async function proxyRequest(req: ServerRequest): Promise<void> {
   req.respond(resp);
 }
 
-main();
+console.log(`Proxy listening on http://${addr}/`);
+for await (const req of server) {
+  proxyRequest(req);
+}