title: expected an assignment or function call and instead saw an expression react
body: <p>i'am getting that erreur 
  on those lines (127 / 130 / 138)
  i don't know what is exactly wrong with the code but i guess it's a syntaxe erreur or something like that ??
  any help with that
  the same code works fine in react-script 1.1.0
  ps i'm using react-script 3.0.0</p>
  
  <pre><code>handleDBReponse(response) {
      const appointments = response;
      const today = moment().startOf("day"); //start of today 12 am
      const initialSchedule = {};
      initialSchedule[today.format("YYYY-DD-MM")] = true;
      const schedule = !appointments.length
        ? initialSchedule
        : appointments.reduce((currentSchedule, appointment) =&gt; {
            const { slot_date, slot_time } = appointment;
            const dateString = moment(slot_date, "YYYY-DD-MM").format(
              "YYYY-DD-MM"
            );
         !currentSchedule[slot_date] //line 127
              ? (currentSchedule[dateString] = Array(8).fill(false)) 
              : null;
            Array.isArray(currentSchedule[dateString]) //line130
  
              ? (currentSchedule[dateString][slot_time] = true)
              : null;
            return currentSchedule;
          }
          , initialSchedule);
  
      for (let day in schedule) {
        let slots = schedule[day];  //138
        slots.length
          ? slots.every(slot =&gt; slot === true)
            ? (schedule[day] = true)
            : null
          : null;
      }
  </code></pre>