[esnext] prototype runtime implementation for async functions

test/mjsunit/harmony/async-await-basic.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-async-await
+
+// TODO(caitp): give async functions a non-constructor map
+
+// Let F be ! FunctionAllocate(functionPrototype, Strict, "non-constructor")
+//async function asyncNonConstructorDecl() {}
+//assertThrows(
+//    () => new asyncNonConstructorDecl(), TypeError);
+//assertThrows(
+//    () => new (async function() {}), TypeError);
+//assertThrows(
+//    () => new ({ async nonConstructor() {} }).nonConstructor(), TypeError);
+//assertThrows(
+//    () => new (() => "not a constructor!"), TypeError);
+
+// Normal completion
+async function asyncDecl() { return "test"; }
+assertEqualsAsync("test", asyncDecl);
+assertEqualsAsync("test2", async function() { return "test2"; });
+assertEqualsAsync("test3", async () => "test3");
+assertEqualsAsync("test4", () => ({ async f() { return "test4"; } }).f());
+
+class MyError extends Error {};
+
+// Throw completion
+async function asyncDeclThrower(e) { throw new MyError(e); }
+assertThrowsAsync(() => asyncDeclThrower("boom!"), MyError, "boom!");
+assertThrowsAsync(
+  () => (async function(e) { throw new MyError(e); })("boom!!!"),
+  MyError, "boom!!!");
+//assertThrowsAsync(
+//  () => (async e => { throw new MyError(e) })("boom!!"), MyError, "boom!!");
+assertThrowsAsync(
+  () => ({ async thrower(e) { throw new MyError(e); } }).thrower("boom!1!"),
+  MyError, "boom!1!");
+
+function resolveLater(value) { return Promise.resolve(value); }
+function rejectLater(error) { return Promise.reject(error); }
+
+// Resume after Normal completion
+var log = [];
+async function resumeAfterNormal(value) {
+  log.push("start:" + value);
+  value = await resolveLater(value + 1);
+  log.push("resume:" + value);
+  value = await resolveLater(value + 1);
+  log.push("resume:" + value);
+  return value + 1;
+}
+
+assertEqualsAsync(4, () => resumeAfterNormal(1));
+assertEquals("start:1 resume:2 resume:3", log.join(" "));
+
+var O = {
+  async resumeAfterNormal(value) {
+    log.push("start:" + value);
+    value = await resolveLater(value + 1);
+    log.push("resume:" + value);
+    value = await resolveLater(value + 1);
+    log.push("resume:" + value);
+    return value + 1;
+  }
+};
+log = [];
+assertEqualsAsync(5, () => O.resumeAfterNormal(2));
+assertEquals("start:2 resume:3 resume:4", log.join(" "));
+
+var resumeAfterNormalArrow = async (value) => {
+  try {
+  log.push("start:" + value);
+  value = await resolveLater(value + 1);
+  log.push("resume:" + value);
+  value = await resolveLater(value + 1);
+  log.push("resume:" + value);
+  return value + 1;
+  } catch (e) {
+    print(e.stack);
+  }
+};
+log = [];
+assertEqualsAsync(6, () => resumeAfterNormalArrow(3));
+assertEquals("start:3 resume:4 resume:5", log.join(" "));
+
+// Resume after Throw completion
+async function resumeAfterThrow(value) {
+  log.push("start:" + value);
+  try {
+    value = await rejectLater("throw1");
+  } catch (e) {
+    log.push("resume:" + e);
+  }
+  try {
+    value = await rejectLater("throw2");
+  } catch (e) {
+    log.push("resume:" + e);
+  }
+  return value + 1;
+}
+
+log = [];
+assertEqualsAsync(2, () => resumeAfterThrow(1));
+assertEquals("start:1 resume:throw1 resume:throw2", log.join(" "));
+
+var O = {
+  async resumeAfterThrow(value) {
+    log.push("start:" + value);
+    try {
+      value = await rejectLater("throw1");
+    } catch (e) {
+      log.push("resume:" + e);
+    }
+    try {
+      value = await rejectLater("throw2");
+    } catch (e) {
+      log.push("resume:" + e);
+    }
+    return value + 1;
+  }
+}
+log = [];
+assertEqualsAsync(3, () => O.resumeAfterThrow(2));
+assertEquals("start:2 resume:throw1 resume:throw2", log.join(" "));
+
+var resumeAfterThrowArrow = async (value) => {
+  log.push("start:" + value);
+  try {
+    value = await rejectLater("throw1");
+  } catch (e) {
+    log.push("resume:" + e);
+  }
+  try {
+    value = await rejectLater("throw2");
+  } catch (e) {
+    log.push("resume:" + e);
+  }
+ return value + 1;
+};
+
+log = [];
+
+assertEqualsAsync(4, () => resumeAfterThrowArrow(3));
+assertEquals("start:3 resume:throw1 resume:throw2", log.join(" "));