Use async/await for internal readAsync function. NFC

Followup to #23104.

Author: sbc100

src/node_shell_read.js

@@ -14,13 +14,9 @@ readBinary = (filename) => {
   return ret;
 };
 
-readAsync = (filename, binary = true) => {
+readAsync = async (filename, binary = true) => {
   // See the comment in the `readBinary` function.
   filename = isFileURI(filename) ? new URL(filename) : filename;
-  return new Promise((resolve, reject) => {
-    fs.readFile(filename, binary ? undefined : 'utf8', (err, data) => {
-      if (err) reject(err);
-      else resolve(binary ? data.buffer : data);
-    });
-  });
+  var data = fs.readFileSync(filename, binary ? undefined : 'utf8');
+  return binary ? data.buffer : data;
 };

src/shell.js

@@ -300,11 +300,7 @@ if (ENVIRONMENT_IS_SHELL) {
     return data;
   };
 
-  readAsync = (f) => {
-    return new Promise((resolve, reject) => {
-      setTimeout(() => resolve(readBinary(f)));
-    });
-  };
+  readAsync = async (f) => readBinary(f);
 
   globalThis.clearTimeout ??= (id) => {};
 

src/web_or_worker_shell_read.js

@@ -16,7 +16,7 @@
   }
 #endif
 
-  readAsync = (url) => {
+  readAsync = async (url) => {
 #if ENVIRONMENT_MAY_BE_WEBVIEW
     // Fetch has some additional restrictions over XHR, like it can't be used on a file:// url.
     // See https://github.com/github/fetch/pull/92#issuecomment-140665932
@@ -41,11 +41,9 @@
 #elif ASSERTIONS
     assert(!isFileURI(url), "readAsync does not work with file:// URLs");
 #endif
-    return fetch(url, {{{ makeModuleReceiveExpr('fetchSettings', "{ credentials: 'same-origin' }") }}})
-      .then((response) => {
-        if (response.ok) {
-          return response.arrayBuffer();
-        }
-        return Promise.reject(new Error(response.status + ' : ' + response.url));
-      })
+    var response = await fetch(url, {{{ makeModuleReceiveExpr('fetchSettings', "{ credentials: 'same-origin' }") }}});
+    if (response.ok) {
+      return response.arrayBuffer();
+    }
+    throw new Error(response.status + ' : ' + response.url);
   };

test/other/codesize/test_codesize_cxx_ctors1.gzsize

@@ -1 +1 @@
-8592
+8575

test/other/codesize/test_codesize_cxx_ctors1.jssize

@@ -1 +1 @@
-21002
+20991

test/other/codesize/test_codesize_cxx_ctors2.gzsize

@@ -1 +1 @@
-8578
+8559

test/other/codesize/test_codesize_cxx_ctors2.jssize

@@ -1 +1 @@
-20969
+20958

test/other/codesize/test_codesize_cxx_except.gzsize

@@ -1 +1 @@
-9626
+9609

test/other/codesize/test_codesize_cxx_except.jssize

@@ -1 +1 @@
-24845
+24834

test/other/codesize/test_codesize_cxx_except_wasm.gzsize

@@ -1 +1 @@
-8562
+8543