I'm having trouble getting my hook to work

Question

The value of my timeDifference variable is not getting set in the code below. What am I doing wrong? My theDiff variable does contain a value, but when I run my setTimeDifference call it doesn't not set timeDifference to that value.

const[timeDifference, setTimeDifference] = useState();

const getTimeDifference = (signInTime) => {
    let now = Date().toLocaleString();
    let timeIn = new Date(signInTime);

    now = moment(now);
    timeIn = moment(timeIn);
    let theDiff = moment(now).diff(moment(timeIn), 'minutes');
    setTimeDifference(theDiff);
}

useEffect(() => { 
    getTimeDifference(props.timein);
    console.log(timeDifference);              
}, []);

Does this answer your question? [Why calling react setState method doesn't mutate the state immediately?](https://stackoverflow.com/questions/30782948/why-calling-react-setstate-method-doesnt-mutate-the-state-immediately) — Ajeet Shah, Mar 18 '21 at 17:00
As you are using hook, check this: https://stackoverflow.com/q/54069253/2873538 — Ajeet Shah, Mar 18 '21 at 17:02

score 0 · Answer 1 · answered Mar 18 '21 at 19:13

Every value referenced inside the effect function should also appear in the dependencies array. Try this:

useEffect(() => { 
    getTimeDifference(props.timein);
    console.log(timeDifference);              
}, [props.timein,setTimeDifference,timeDifference]);

I'm having trouble getting my hook to work

1 Answers1