I have a Rails project that we converted from Rails 5.0 to Rails 5.1.0. When I try to precompile the assets, I get the following error message:
Yarn executable was not detected in the system.
Download Yarn at https://yarnpkg.com/en/docs/install
Everything I read from an internet search says yarn and webpacker comes with Rails 5.1. I get the following from check the rails version.
$rails --version
Rails 5.1.0
How do I fix this? I'd also like to know what is happening.
Rails 5.1 comes with SUPPORT for yarn and webpack, but you need to install them yourself. Yarn is a package manager and webpack is a package.
Follow instruction at https://yarnpkg.com/lang/en/docs/install/ to install Yarn in your system and then add webpack to your project like:
yarn add --dev webpack webpack-dev-server
Additionally, the message you're seeing is warning, rather than straight up error. If you do not need to use any of the fancy js packages, you can just use good ol' asset pipeline
You could just remove bin/yarn from your App directory if you're not using yarn/webpacker to avoid the log message.
来源：https://stackoverflow.com/questions/45486362/rails-precompile-assets-yarn-executable-was-not-detected