Update and test promise detection

Author: mrbbot

html_rewriter.js.patch

@@ -200,7 +200,7 @@
  module.exports.__wbg_instanceof_Promise_c6535fc791fcc4d2 = function(arg0) {
 -    var ret = getObject(arg0) instanceof Promise;
 +    var obj = getObject(arg0);
-+    var ret = (obj instanceof Promise) || (typeof obj === "object" && typeof obj.then === "function");
++    var ret = (obj instanceof Promise) || (Object.prototype.toString.call(obj) === '[object Promise]');
      return ret;
  };
 

test/misc.spec.ts

@@ -1,4 +1,5 @@
 import { TextEncoder, TextDecoder } from "util";
+import vm from "vm";
 import test from "ava";
 import { HTMLRewriter as RawHTMLRewriter } from "..";
 import { HTMLRewriter, wait } from ".";
@@ -137,3 +138,18 @@ test("rewriter allows chaining", (t) => {
   t.is(rewriter.on("p", {}), rewriter);
   t.is(rewriter.onDocument({}), rewriter);
 });
+
+test.serial("handles async handler in different realm", async (t) => {
+  const context = vm.createContext({HTMLRewriter, wait});
+  const res = await vm.runInContext(`
+  const rewriter = new HTMLRewriter();
+  rewriter.on("p", {
+    async element(element) {
+      await wait(50);
+      element.setInnerContent("new");
+    },
+  });
+  rewriter.transform("<p>old</p>");
+  `, context);
+  t.is(res, "<p>new</p>");
+});