Modern Front-End Development for Rails, 2nd Edition

Yarn Holds It All Together

I find it a little hard to get my head around what some of these JavaScript tools are supposed to be doing, in part because they can be a little abstract. Instead, I find it easier to discuss what problems esbuild and its related tools are solving for us. As far as our Rails app is concerned, we’re juggling two external pieces of software that solve related problems for our client-side code: Yarn and esbuild.

The problem Yarn is designed to solve is: “What version of all my dependent modules does my program rely on?” Yarn is for JavaScript and npm modules what Bundler is for Ruby gems. All the JavaScript packaging tools supported by jsbundling—esbuild, rollup, and webpack—use Yarn and the package.json file ...