How to access URL params in useEffect?

Question

I have a functional component where I am trying to access URL params that have been namespaced in react-router via a hook.

useEffect(() => {
    document.title = props.match.params.subject

    UserServices.getSubject(props.match.params.subject)
      .then(resp => {
        if (resp.data.lectures !== undefined) {
          setLectures(resp.data.lectures)
          mountLecture(resp.data.lectures[0].title)
        }
      })
  }, [])

useEffect(() => {
    if(props.match.params.title) mountLecture(props.match.params.title)
    else mountLecture(lectures[0].title)
  }, [props.match.params])

However, it keeps telling me can't read the property title of undefined, even though it comes out in a console log.

Answer 1

So I decided to combine the useEffect hooks since I only needed them to run once.

Then I used the if statement to check the params before calling 'setLectures()'. Something interesting to note, when I called setLectures() before the if statement (to be DRY), then console.log the params. It returned the last item of the array in the UserServices response data.

  useEffect(() => {
    document.title = props.match.params.subject

    UserServices.getSubject(props.match.params.subject)
      .then(resp => {
          console.log(props.match.params.title)
          if (props.match.params.title !== undefined) {
            setLectures(resp.data.lectures)
            mountLecture(props.match.params.title)
            console.log(1)
          }
          else {
            setLectures(resp.data.lectures)
            console.log(10)
            mountLecture(resp.data.lectures[0].title)
          }
      })
  }, [])