How does the module map deal with relative paths?

[littledan]

Lots of JS environments use module specifiers which could be either relative or absolute paths. In this case, the module specifier is usually converted into an absolute form, and then that absolute path is used as the key in the module map. However, the conversion/normalization is often done in a host-specific way (since different systems have different specifier syntaxes).

How does the moduleMap of Compartments enable paths to be made absolute, so they can serve as cache keys? What even is the type of the moduleMap exactly?

[dckc]

In at least one experiment (https://gist.github.com/jfparadis/cfd2e965047131fcfac1cb81fdb9b863), the moduleMap is an object map from referrer to specifier to target, where target is a key in a parent Compartment map.

[littledan]

@dckc Thanks for the background. Oh wow, so it's fully denormalized, and you have to pre-calculate all of these referrers to fill in the map? I wonder how practical that is.

[dckc]

Yes, the stuff I've seen kicked around so far is fully denormalized. We'll see how it turns out...