vite/playground/module-graph/vite.config.ts

import { defineConfig } from 'vite'
import type { Plugin } from 'vite'

export default defineConfig({
  plugins: [slowModulePlugin()],
})

function slowModulePlugin(): Plugin {
  return {
    name: 'slow-module',
    resolveId(id) {
      if (id === 'virtual:slow-module') {
        return '\0virtual:slow-module'
      }
    },
    async load(id) {
      if (id === '\0virtual:slow-module') {
        await new Promise((resolve) => setTimeout(resolve, 500))
        return `export const msg = '[success]'`
      }
    },
  }
}