/**
 * eventBus
 */
class EventBus {
  constructor() {
    this.events = {}
  }
  /**
   * @description: on
   */
  on(event, callback) {
    if (!this.events[event]) {
      this.events[event] = []
    }
    this.events[event].push(callback)
  }
  /**
   * @description: once
   */
  once(event, callback) {
    const fn = (...args) => {
      callback(...args)
      this.off(event, fn)
    }
    this.on(event, fn)
  }
  /**
   * @description: off
   */
  off(event, callback) {
    if (!this.events[event]) {
      return
    }
    this.events[event] = this.events[event].filter((cb) => cb !== callback)
  }
  /**
   * @description: emit
   */
  emit(event, ...args) {
    if (!this.events[event]) {
      return
    }
    this.events[event].forEach((cb) => cb(...args))
  }
}

const eventBus = new EventBus()
export default eventBus