verify-treeshaking.js

// @ts-check
import fs from 'node:fs'
import { exec } from './utils.js'

exec('pnpm', ['build', 'vue', '-f', 'global-runtime'])
  .then(() => {
    const errors = []

    const devBuild = fs.readFileSync(
      'packages/vue/dist/vue.runtime.global.js',
      'utf-8',
    )

    if (devBuild.includes('__spreadValues')) {
      errors.push(
        'dev build contains unexpected esbuild object spread helper.\n' +
          'This means { ...obj } syntax is used in runtime code. This should be ' +
          'refactored to use the `extend` helper to avoid the extra code.',
      )
    }

    const prodBuild = fs.readFileSync(
      'packages/vue/dist/vue.runtime.global.prod.js',
      'utf-8',
    )

    if (prodBuild.includes('Vue warn')) {
      errors.push(
        'prod build contains unexpected warning-related code.\n' +
          'This means there are calls of warn() that are not guarded by the __DEV__ condition.',
      )
    }

    if (
      prodBuild.includes('html,body,base') ||
      prodBuild.includes('svg,animate,animateMotion') ||
      prodBuild.includes('annotation,annotation-xml,maction')
    ) {
      errors.push(
        'prod build contains unexpected domTagConfig lists.\n' +
          'This means helpers like isHTMLTag() is used in runtime code paths when it should be compiler-only.',
      )
    }

    if (errors.length) {
      throw new Error(
        `Found the following treeshaking errors:\n\n- ${errors.join('\n\n- ')}`,
      )
    }
  })
  .catch(error => {
    console.error(`Treeshaking verification failed: ${error.message}`)
    process.exit(1)
  })