实现Vue3/Nuxt3 预览excel文件

安装必要的库
```
npm install xlsx
```

创建一个组件来处理文件上传和解析：
在src/components 目录下创建一个名为 ExcelPreview.vue 的文件

<template>
<div>
<input type="file" @change="handleFileUpload" />
<table v-if="sheetData.length">
<thead><tr><th v-for="(header, index) in sheetData[0]" :key="index">{{ header }}</th></tr></thead>
<tbody><tr v-for="(row, rowIndex) in sheetData.slice(1)" :key="rowIndex"><td v-for="(cell, cellIndex) in row" :key="cellIndex">{{ cell }}</td></tr></tbody>
</table>
</div>
</template>

<script setup lang="ts">
import { ref } from 'vue';
import * as XLSX from 'xlsx';

const sheetData = ref([]);

const handleFileUpload = (event: Event) => {
  const file = (event.target as HTMLInputElement).files?.[0];
  if (file) {
    const reader = new FileReader();
    reader.onload = (e) => {
      const data = new Uint8Array(e.target?.result as ArrayBuffer);
      const workbook = XLSX.read(data, { type: 'array' });
      const firstSheetName = workbook.SheetNames[0];
      const worksheet = workbook.Sheets[firstSheetName];
      sheetData.value = XLSX.utils.sheet_to_json(worksheet, { header: 1 });
    };
    reader.readAsArrayBuffer(file);
  }
};
</script>

如果excel文件是后台返回的一个链接，需要重新请求解析成ArrayBuffer，
以下是nuxt3 示例：


// 为了解决跨域问题，在server/api 下 创建一个请求api， downloadFileByProxy.ts
import { defineEventHandler } from 'h3';

export default defineEventHandler(async event => {
  const { filePath } =  getQuery(event);
  let matches = filePath?.match(/^https?\:\/\/([^\/?#]+)(?:[\/?#]|$)/i);
  let domain = matches && matches[1]; 
  return proxyRequest(event,`https://${domain}/`, {
    fetch: ()=>fetch(filePath),
  })
})

在ExcelPreview.vue 文件中：

  async function getFile(path: string) {
    // download pdf from api to prevent CORS
    const { _data } = await $fetch.raw(`/api/downloadFileByProxy`, {
      method: 'get',
      params: {
        filePath: path,
      },
    });
    let blob = _data;
    let buffer = await blob?.arrayBuffer();
    return buffer;
  }

  const debounceRenderHandle = debounce(async () => {
    bufferCache.value = bufferCache.value || (await getFile(props.path)); // bufferCache这里是用来处理缓存，可以视具体情况加这个变量与否
    const data = new Uint8Array(bufferCache.value as ArrayBuffer);
    const workbook = XLSX.read(data, { type: 'array' });
    const firstSheetName = workbook.SheetNames[0];
    const worksheet = workbook.Sheets[firstSheetName];
    sheetData.value = XLSX.utils.sheet_to_json(worksheet, { header: 1 });
  }, 500);

实现Vue3/Nuxt3 预览excel文件

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