[woodrowbarlow]

i would say make it a boolean flag, default to false, with a comment that says "this must be enabled for packages which use the local filesystem or OS APIs". if wasm delivers on its potential, OS-level interactions would really be the only valid use case (and legacy code, which should be considered a little bit inherently unsafe anyway).

perhaps yarn could even develop official packages which include native code that wraps all the most relevant OS APIs, and the default setting of the flag would allow only those native packages.

this is all pretty far down the road anyway.