vue3写一个弹窗

好的，下面是一个简单的弹窗组件的代码示例：

<template>
  <div v-if="show">
    <div class="modal-wrapper">
      <div class="modal">
        <div class="modal-header">
          <h3>{{ title }}</h3>
          <button @click="close">X</button>
        </div>
        <div class="modal-body">
          {{ message }}
        </div>
        <div class="modal-footer">
          <button @click="close">关闭</button>
        </div>
      </div>
    </div>
    <div class="modal-overlay"></div>
  </div>
</template>

<script>
export default {
  props: {
    show: {
      type: Boolean,
      required: true
    },
    title: {
      type: String,
      default: ""
    },
    message: {
      type: String,
      default: ""
    }
  },
  methods: {
    close() {
      this.$emit("close");
    }
  }
};
</script>

<style scoped>
.modal-wrapper {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 9999;
  background-color: #fff;
  padding: 20px;
  border-radius: 5px;
  box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.5);
}

.modal {
  max-width: 600px;
  margin: 0 auto;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.modal-header h3 {
  margin: 0;
}

.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 9998;
}
</style>

使用时，可以在父组件中引入该组件，并通过 `v-show` 或 `v-if` 控制其显示或隐藏：

<template>
  <div>
    <button @click="showModal = true">点击打开弹窗</button>
    <modal :show="showModal" title="提示" message="这是一个弹窗！" @close="showModal = false" />
  </div>
</template>

<script>
import Modal from "./Modal.vue";

export default {
  components: {
    Modal
  },
  data() {
    return {
      showModal: false
    };
  }
};
</script>

以上代码实现了一个简单的弹窗，点击按钮后会显示弹窗，点击关闭按钮或弹窗外部的遮罩层可以关闭弹窗。