In the last lecture, I made a small typo - handleSubmit should look like this:

function handleSubmit(event: FormEvent<HTMLFormElement>) {
    event.preventDefault();
 
    const enteredGoal = goalRef.current!.value;
    const enteredSummary = summaryRef.current!.value;
 
    // validation...
    onAdd(enteredGoal, enteredSummary);
  }