build.config.ts

// build.config.ts
import { defineBuildConfig } from 'unbuild'
import { babel } from '@rollup/plugin-babel'

export default defineBuildConfig({
  replace: {
    'import.meta.vitest': 'undefined',
  },
  hooks: {
    'rollup:options'(_ctx, options) {
      if (!Array.isArray(options.plugins)) {
        if (options.plugins != null && typeof options.plugins !== 'boolean') {
          options.plugins = [options.plugins]
        } else {
          options.plugins = []
        }
      }

      for (let i = 0, l = options.plugins.length; i < l; i++) {
        const plugin = options.plugins[i]

        if (
          typeof plugin === 'object' &&
          plugin != null &&
          !Array.isArray(plugin) &&
          !('then' in plugin)
        ) {
          if (plugin.name === 'esbuild') {
            options.plugins[i] = babel({
              babelHelpers: 'bundled',
              extensions: ['.ts', '.js', '.cjs', '.mjs', '.es', '.es6'],
              presets: [
                '@babel/preset-typescript',
                [
                  '@babel/preset-env',
                  {
                    targets: '>= .3% and not dead, node > 16',
                  },
                ],
              ],
            })
          }
        }
      }
    },
  },
})