使用事件总线(eventbus)或自定义事件的问题

<!-- 组件A -->
<template>
  <div>
    <button @click="jump">跳转B</button>
    {{msg}}
  </div>
</template>

<!-- 组件B -->
<template>
  <div>
    <button @click="back">返回</button>
  </div>
</template>

// A
jump () {
  this.$router.push('/b')
}

// B
back () {
	this.$router.go(-1)
}

// A
getData (e) {
    this.msg = e.detail.msg
}

beforeCreate () {
	window.addEventListener('cancel', this.getData)
}

destoryed () {
	window.removeEventListener('cancel', this.getData)
}

// B
dispatchEvent () {
	const cancelEvent = new CustomEvent('cancel', {
		detail: {
			msg: '结果'
        }
    })
    window.dispatchEvent(cancelEvent)
    console.log('触发')
}

beforeDestroy () {
	this.dispatchEvent()
}

// main.js
window.eventBus = new Vue()

// A
beforeCreate () {
	eventBus.$off('cancel')
	eventBus.$on('cancel', data => {
		this.msg = data
	})
}

// B
beforeDestroy () {
	eventBus.$emit('cancel', {msg: '结果'})
}