React Error on 25+5 clock

Tell us what’s happening:
Describe your issue in detail here.

So I am currently doing the final project in the Front End Development Libraries

However I am experiencing a React error on the timeout variable in the clock function error message is displaying
"Expected an assignment or function call and instead saw an expression "

Here is the snippet of the code I am working on.
Your code so far

let timeout = setTimeout(() => {
        if (playTimer && timeNow) {
            setTimeNow(timeNow - 1);
}, 1000);

const startTimer = () => {
        setPlayTimer(prev => !prev)

const clock = () => {
        if (playTimer){
            timeout; // error is pointing here
        } else{

useEffect(() => {
}, [playTimer, timeout, timeNow]);
  **Your browser information:**

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:98.0) Gecko/20100101 Firefox/98.0

The error is only showing itself when I do npm start in VScode but it works fine on codepen as seen here **It even passes the whole test on codepen **
But it doesnt display when I do npm start.
Can anyone help me solve the issue?

const num = 9
bla bla

“const num = 9” is doing something but “num” is not.