get rid of false timer id

src/utils/focusTimeout.js

@@ -7,7 +7,7 @@ document.addEventListener('visibilitychange', () => {
     outOfFocusStart = Date.now()
   } else {
     timeOutOfFocus += Date.now() - outOfFocusStart
-    suspendedTimeouts.forEach(({ callback, startTime }) => setFocusTimeout(callback, timeOutOfFocus - startTime))
+    suspendedTimeouts.forEach(({ callback, startTime, setTimerId }) => setTimerId(setFocusTimeout(callback, timeOutOfFocus - startTime)()))
     outOfFocusStart = null;
   }
 });
@@ -17,19 +17,25 @@ document.addEventListener('visibilitychange', () => {
  *
  * @param {function(*): ()} [callback] - A function that will be invoked after passed time
  * @param {number} [milliseconds] - Minimum duration (in milliseconds) that the callback will be executed after
- * @returns {number} - timer id
+ * @returns {function(*): (number)} - Getter function for current timer id
  */
 export default function setFocusTimeout(callback, milliseconds) {
   const startTime = timeOutOfFocus;
-  const timerId = setTimeout(() => {
+  let timerId = setTimeout(() => {
     if (timeOutOfFocus === startTime && outOfFocusStart == null) {
       callback();
     } else if (outOfFocusStart != null) {
       // case when timeout ended during page is out of focus
-      suspendedTimeouts.push({ callback, startTime })
+      suspendedTimeouts.push({
+        callback,
+        startTime,
+        setTimerId(newId) {
+          timerId = newId;
+        }
+      })
     } else {
-      setFocusTimeout(callback, timeOutOfFocus - startTime);
+      timerId = setFocusTimeout(callback, timeOutOfFocus - startTime)();
     }
   }, milliseconds);
-  return timerId;
+  return () => timerId;
 }

src/utils/ttlCollection.js

@@ -47,7 +47,7 @@ export function ttlCollection(
     if (pendingPurge.length > 0) {
       const now = timestamp();
       nextPurge = Math.max(now, pendingPurge[0].expiry + slack);
-      task = setFocusTimeout(() => {
+      const getTaskId = setFocusTimeout(() => {
         const now = timestamp();
         let cnt = 0;
         for (const entry of pendingPurge) {
@@ -66,6 +66,7 @@ export function ttlCollection(
         task = null;
         reschedulePurge();
       }, nextPurge - now);
+      task = getTaskId();
     } else {
       task = null;
     }

test/spec/unit/utils/focusTimeout_spec.js

@@ -45,4 +45,16 @@ describe('focusTimeout', () => {
     clock.tick(2000);
     expect(callback.called).to.be.true;
   });
+
+  it('should return updated timerId after page was showed again', () => {
+    let callback = sinon.stub();
+    const getCurrentTimerId = setFocusTimeout(callback, 4000);
+    const oldTimerId = getCurrentTimerId();
+    clock.tick(2000);
+    setDocumentHidden(true);
+    clock.tick(2000);
+    setDocumentHidden(false);
+    const newTimerId = getCurrentTimerId();
+    expect(oldTimerId).to.not.equal(newTimerId);
+  });
 });