vite.config.js

import { defineConfig } from 'vite';
import vue from '@vitejs/plugin-vue';

// https://vitejs.dev/config/
export default defineConfig({
  plugins: [
    vue(),
    {
      name: 'my-plugin',
      apply: 'build',
      transformIndexHtml(html) {
        return [
          {
            tag: 'script',
            children: `
            (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
            new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
            j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
            'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
            })(window,document,'script','dataLayer','GTM-XXXXXX');
            `,
            injectTo: 'head',
          },
          {
            tag: 'noscript',
            children: ``,
            injectTo: 'body',
          },
        ];
      },
    },
  ],
});