Fix for #483 and jestjs/jest#14549

src/fake-timers-src.js

@@ -47,13 +47,13 @@
 
 /**
  * @typedef RequestAnimationFrame
  * @property {function(number):void} requestAnimationFrame
  * @returns {number} - the id
  */
 
 /**
  * @typedef Performance
  * @property {function(): number} now
  */
 
 /* eslint-disable jsdoc/require-property-description */
@@ -307,7 +307,7 @@
         return timer && timer.callAt >= from && timer.callAt <= to;
     }
 
     /**
      * @param {Clock} clock
      * @param {Timer} job
      */
@@ -658,7 +658,7 @@
     }
 
     /* eslint consistent-return: "off" */
     /**
      * Timer comparitor
      *
      * @param {Timer} a
@@ -790,7 +790,7 @@
         }
     }
 
     /**
      * Gets clear handler name for a given timer type
      *
      * @param {string} ttype
@@ -802,7 +802,7 @@
         return `clear${ttype}`;
     }
 
     /**
      * Gets schedule handler name for a given timer type
      *
      * @param {string} ttype
@@ -814,7 +814,7 @@
         return `set${ttype}`;
     }
 
     /**
      * Creates an anonymous function to warn only once
      */
     function createWarnOnce() {
@@ -826,7 +826,7 @@
     }
     const warnOnce = createWarnOnce();
 
     /**
      * @param {Clock} clock
      * @param {number} timerId
      * @param {string} ttype
@@ -1015,8 +1015,8 @@
 
     /**
      * @typedef {object} Timers
      * @property {setTimeout} setTimeout
      * @property {clearTimeout} clearTimeout
      * @property {setInterval} setInterval
      * @property {clearInterval} clearInterval
      * @property {Date} Date
@@ -1578,6 +1578,8 @@
                     function doRun() {
                         originalSetTimeout(function () {
                             try {
+                                runJobs(clock);
+
                                 let numTimers;
                                 if (i < clock.loopLimit) {
                                     if (!clock.timers) {
@@ -1633,6 +1635,7 @@
                         try {
                             const timer = lastTimer(clock);
                             if (!timer) {
+                                runJobs(clock);
                                 resolve(clock.now);
                             }
 

test/issue-483-test.js

@@ -0,0 +1,34 @@
+"use strict";
+
+const FakeTimers = require("../src/fake-timers-src");
+const sinon = require("sinon");
+const assert = require("assert");
+
+function myFn(cb) {
+    queueMicrotask(() => cb());
+}
+
+describe("async time skippers should run microtasks", function () {
+    let clock;
+    const timers = ["runAllAsync", "runToLastAsync"];
+
+    afterEach(function () {
+        clock.uninstall();
+    });
+
+    beforeEach(function setup() {
+        clock = FakeTimers.install({ toFake: ["queueMicrotask"] });
+    });
+
+    // eslint-disable-next-line mocha/no-setup-in-describe
+    timers.forEach((fastForward) => {
+        it(`should advance past queued microtasks using ${fastForward}`, async function () {
+            const cb = sinon.fake();
+            myFn(cb);
+            myFn(cb);
+            myFn(cb);
+            await clock[fastForward]();
+            assert.equal(cb.callCount, 3);
+        });
+    });
+});