defineEmits 提示 emit is not a function

`defineEmits` is a feature in Vue 3 that allows you to define custom events that a component can emit. The error message "emit is not a function" suggests that you might be trying to emit an event without defining it first.

To use `defineEmits`, you need to import it from the `vue` package and define the events in the component's options object. Here's an example:

import { defineComponent, defineEmits } from 'vue'

export default defineComponent({
  emits: ['my-event'],
  methods: {
    handleClick() {
      this.$emit('my-event', { data: 'some data' })
    }
  }
})

In this example, we're defining a custom event called "my-event" using the `emits` option. Then, in a component method, we're emitting the event using `$emit`. Make sure the component that emits the event has the `emits` option defined.