[sebastianmck]

Hey! I'm Sebastian McKenzie (@kittens on GitHub) and I'm the lead develop on Yarn at Facebook. We initially used a method similar to ied when we first started experimenting with internal usage at Facebook.

We ran into a lot of issues with OS compatibility around symlinks and existing tools not supporting it. Windows lacks support for symlinks on non-Admin accounts, NTFS junctions work but they're slightly quirky in their behaviour and don't behave exactly the same way.

A lot of tooling relies on the existing node_modules structure. ESLint for example will load tools relative to itself which means that they need to be reachable in the tree, you can solve this with hardlinks but there's caveats with that too. Existing tools aren't very well suited for handling cycles either which in a system like npm are extremely common as a transitive module could depend on one that's higher in the graph.

We care a lot about existing ecosystem compatibility and because of these limitations we went with the current status quo. We'll continue to explore others options though and if there's a chance we can do it without any of these caveats then we're more than happy to explore it.

Let me know if you have any further questions!

[cpojer]

As Sebastian said we are more than excited to explore what we can improve in the future. If you are interested, please start a discussion on the GitHub issue tracker: https://github.com/yarnpkg/yarn :)

[blubbi2]

> We initially used a method similar to ied when we first started experimenting with internal usage at Facebook.

Would be really nice if you would e.g. add ied to "Prior art" on your README then. ;)

/ @alexanderGugel (the guy behind ied)