vue的computed如何传值

Question

<template>
  <table>
    <tr>
      <td colspan="4">全校学生统计表</td>
    </tr>
    <tr>
      <td>年级</td>
      <td>班级数量</td>
      <td>班级人数</td>
      <td>年级人数</td>
    </tr>
  </table>
  <table v-for="(index) in nj" :key="index">
    <tr>
      <td>{{ nj[index] }}</td>
      <td>{{ bjCount[index] }}</td>
      <td>{{ bjNumber[index] }}</td>
      <td>{{ njNumber(index) }}</td>
    </tr>
  </table>
  <div>总计:{{ Count }}人</div>
</template>

<script setup>
import { computed } from 'vue'

const nj = [1, 2, 3, 4, 5, 6]
const bjCount = [3, 4, 3, 4, 4, 5]
const bjNumber = [30, 35, 40, 35, 40, 30]
let value

const njNumber = (index) => {
  value = computed(() => {
    return bjCount[index] * bjNumber[index]
  })
}

const Count = () => {
  let count = 0
  for (let i = 0; i < nj.length; i++) {
    njNumber(i)
    count += value
  }
  return count
}

</script>

<style scoped>
table {
  margin: 0 auto;
}

td {
  border: black solid 1px;
  width: 100px;
}
</style>

为啥我的预览结果是这样的,谁能 帮我看下什么问题

Answer 1

computed应该被用于创建计算属性，而不是在计算属性中使用

<template>
    <table>
        <tr>
            <td colspan="4">全校学生统计表</td>
        </tr>
        <tr>
            <td>年级</td>
            <td>班级数量</td>
            <td>班级人数</td>
            <td>年级人数</td>
        </tr>
    </table>
    <table v-for="(item，index，key) in nj" :key="index">
        <tr>
            <td>{{ nj[index] }}</td>
            <td>{{ bjCount[index] }}</td>
            <td>{{ bjNumber[index] }}</td>
            <td>{{ njNumber(index) }}</td>
        </tr>
    </table>
    <div>总计:{{ Count }}人</div>
</template>

<script setup>
import { computed } from 'vue'

const nj = [1, 2, 3, 4, 5, 6]
const bjCount = [3, 4, 3, 4, 4, 5]
const bjNumber = [30, 35, 40, 35, 40, 30]

const njNumber = (index) => {
    return bjCount[index] * bjNumber[index]
}

const Count = computed(() => {
    let count = 0
    for (let i = 0; i < nj.length; i++) {
        count += njNumber(i)
    }
    return count
})
</script>

<style scoped>
table {
    margin: 0 auto;
}

td {
    border: black solid 1px;
    width: 100px;
}
</style>