David Kimura PRO said about 4 years ago on FullCalendar Events and Scheduling :
Here is a working example with a Stimulus Controller for Full Calendar v4+ (jQuery dependency removed)

// yarn add @fullcalendar/core
// yarn add @fullcalendar/daygrid

import { Controller } from "stimulus"
import { Calendar } from '@fullcalendar/core';
import dayGridPlugin from '@fullcalendar/daygrid';
import '@fullcalendar/core/main.css'
export default class extends Controller {
  static targets = ["calendar"]
  initialize() { }

  connect() {
    let calendar = new Calendar(this.calendarTarget, {
      header: {
        left: 'prev,next today',
        center: 'title',
        right: 'dayGridMonth,dayGridWeek,dayGridDay'
      },
      eventLimit: true,
      views: {
        dayGridMonth: {
          eventLimit: 3
        }
      },
      events: '/admin/events.json',
      plugins: [dayGridPlugin]
    })
    calendar.render();

  }

  disconnect() { }
}