问题
Locally I simply run composer install and yarn install, but when pushing to Heroku only composer dependencies get installed, but not Yarn components. I can't seem to find a way for Heroku to trigger Yarn components installation.
回答1:
I just needed to add the heroku/nodejs buildpack inside Heroku application's settings page, alongside the already present heroku/php. The next deploy then also installed the yarn components.
来源：https://stackoverflow.com/questions/48086897/deploy-php-project-with-yarn-to-heroku