docs.sheetjs.com/docz/static/vitejs/vite.config.ts

import { defineConfig } from 'vite'
import vue from '@vitejs/plugin-vue'
import { readFileSync } from 'fs';
import { read, utils } from 'xlsx';

export default defineConfig({
  assetsInclude: ['**/*.xlsx'], // xlsx file should be treated as assets

  plugins: [
    vue(),
    { // this plugin handles ?sheetjs tags
      name: "vite-sheet",
      transform(_code, id) {
        if(!id.match(/\?sheetjs$/)) return;
        var wb = read(readFileSync(id.replace(/\?sheetjs$/, "")));
        var data = utils.sheet_to_json(wb.Sheets[wb.SheetNames[0]]);
        return `export default JSON.parse('${JSON.stringify(data).replace(/\\/g, "\\\\")}')`;
      }
    },
    { // this plugin handles ?html tags
      name: "vite-sheet-html",
      transform(_code, id) {
        if(!id.match(/\?html/)) return;
        var wb = read(readFileSync(id.replace(/\?html/, "")));
        var html = utils.sheet_to_html(wb.Sheets[wb.SheetNames[0]]);
        return (`export default JSON.parse('${JSON.stringify(html).replace(/\\/g, "\\\\")}')`);
      }
    },
    { // this plugin handles ?b64 tags
      name: "vite-b64-plugin",
      transform(_code, id) {
        if(!id.match(/\?b64$/)) return;
        var path = id.replace(/\?b64/, "");
        var data = readFileSync(path, "base64");
        return `export default '${data}'`;
      }
    }
  ]
});