no such file or directory, open '/app/static/ nuxt heroku code example

Example: mern heroku Error: ENOENT: no such file or directory

if (process.env.NODE_ENV) {
    app.use(express.static(path.resolve(process.cwd(), 'client/build')))
    app.get('*', (req, res) => {
      res.sendFile(path.resolve(process.cwd(), 'client/build/index.html'))
    })
  }