Error handling

[zenparsing]

Import maps fail-soft with console warnings. Like import maps, export maps have a fairly restrictive syntax for both keys and values. What should node do when it encounters an invalid key or value?

[jkrems]

I assume we would generally follow precedent set by import maps. There's currently discussions around making export maps work for providing different entrypoints depending on platform (e.g. modern browser, node 6+, etc.) which may force us to go with "ignore invalid entries" to some degree.