这个是footer里的代码。我跑了是没有问题的，不知道你是哪里有问题啊？

<template>

<div class="container">

<div>completed{{ isComplete }} / total {{ list.length }}</div>

<div v-if="isComplete > 0" class="btn">

<button @click="clear">clear completed</button>

</div>

</div>

</template>

<script>

import { defineComponent, ref, computed } from "vue";

export default defineComponent({

name: "navFooter",

props: {

//父组件从vuex中，拿出list的数据

//然后传给子组件，子组件就展示

list: { type: Array, required: true },

},

setup(props, ctx) {

//过滤已完成

let isComplete = computed(() => {

let arr = props.list.filter((item) => {

return item.complete;

});

return arr.length;

});

// let all = ref(3);

let clear = () => {

//过滤未完成,

let arr = props.list.filter((item) => {

return item.complete === false;

});

ctx.emit("clear", arr);

// console.log("clear");

};

return {

isComplete,

// all,

clear,

};

},

});

</script>

<style lang="scss" scoped>

.container {

display: flex;

align-content: center;

}

.btn {

margin-left: 10px;

}

</style>