Question for vendors: Can we reveal host-defined loadHook and resolveHook?

[kriskowal]

Realms and Compartments (as module-loaders) have a host-defined load hook and a resolve hook. In #50, we are considering ways that the host-defined hooks could be passed from host to guest. There is a way to make this work without ever revealing the loadHook or resolveHook to user code, only revealing their behavior as a side-effect of using a compartment. However, the design may be simpler if we simply revealed the host compartment’s hooks, for example as Compartment.loadHook and Compartment.resolveHook static methods, or like a parentLoadHook argument to loadHook.

Would it be possible to expose these functions such that user code could call it directly, or pass it to a new compartment?

Summary of the proposed hooks: loadHook(specifier: string) returns a promise for a “module descriptor”, which in turn may contain a StaticModuleRecord or a synthetic static module record. The descriptor may also provide a bag of importMeta properties, and other module descriptors indicate aliases from one specifier to another. The resolveHook is synchronous and produces memoization table keys from import specifiers and the referrer specifier.

[kriskowal]

@Jamesernator and @naugtur point us at Node.js experimental loader documentation https://nodejs.org/api/esm.html#hooks (via #50 (comment))

Which suggests, categorically, Node.js would be fine revealing its host hooks to guest code. So, we can narrow the question to whether browser vendors could do the same.

[kriskowal]

Capturing for the record, @syg’s feedback:

my intuition is a strong "preferably not" [expose the host hooks]