在util文件夹下生成clickoutside.js

let cache = {};
let key = 1;
export default {
    inserted(el, binding) {
        el.outsideKey = key++;
        const self = {};
        self.documentHandler = (e) => {
        if (el.contains(e.target)) {
            return false;
        }
        if (binding.value) {
            binding.value(e);
        }
        return true;
        };
        cache[el.outsideKey] = self;
        document.addEventListener('click', self.documentHandler);
    },
    unbind(el) {
        const self = cache[el.outsideKey];
        document.removeEventListener('click', self.documentHandler);
        delete cache[el.outsideKey];
    },
};

使用clickoutside

<template>
    <div v-clickoutside="onClickOutside"></div>
</template>
<script>
import Clickoutside from "@/util/clickoutside";

export default {
    directives: { Clickoutside },
    methods: {
        onClickOutside() {
            // ...
        }
    }   
}
</script>

vue3的使用方法参考Vue3 自定义指令：ClickOutside（点击当前区域之外的位置）-CSDN博客