每个人。我正在尝试将mean.io的均值堆栈部署到heroku，但是出现了一些我不理解的错误。实际上在部署过程中，push comand被这样的错误所拒绝：
> remote: ERROR in Cannot read property 'Symbol(Symbol.iterator)' of
> undefined remote: npm ERR! code ELIFECYCLE remote: npm ERR! errno 1
> remote: npm ERR! mean@2.0.2 build: `ng build --prod` remote: npm ERR!
> Exit status 1 remote: npm ERR! remote: npm ERR! Failed at the
> mean@2.0.2 build script. remote: npm ERR! This is probably not a
> problem with npm. There is likely additional logging output above.
> remote: remote: npm ERR! A complete log of this run can be found in:
> remote: npm ERR!
> /tmp/npmcache.urfnC/_logs/2019-05-02T17_46_56_294Z-debug.log remote:
> remote: -----> Build failed remote: remote: We're sorry this
> build is failing! You can troubleshoot common issues here: remote:
> https://devcenter.heroku.com/articles/troubleshooting-node-deploys
> remote: remote: If you're stuck, please submit a ticket so we
> can help: remote: https://help.heroku.com/ remote: remote:
> Love, remote: Heroku remote: remote: ! Push rejected,
> failed to compile Node.js app. remote: remote: ! Push failed
> remote: Verifying deploy... remote: remote: ! Push rejected to
> rednoteapp.