安装mitt成功了的

<script lang='ts'>
import { defineComponent, onUnmounted } from 'vue'
import mitt from 'mitt'
const emitter = mitt()
export default defineComponent({
  emits:['submit'],
  setup(props,context){
    const onSubmit = () => {
      context.emit('submit',true)
    }
    const callback = (test:string) => {
      console.log(test)
    }
    emitter.on('form-item-create', callback)
    onUnmounted(()=>{
      emitter.off('form-item-create', callback) 
    })
    return {
      onSubmit
    }
  }
})
</script>