What exact characters are allowed in the map

[domenic]

Both on the left and right-hand sides?

The only restriction stated in README.md right now is that the right-hand side either starts with ./, ../, or /, or is interpreted as a built-in module.

Do we want to add URL-based constraints? Does percent-decoding happen? Needs an algorithm, either for parsing or validation or both.

[domenic]

The algorithm so far in #67 normalizes and validates roughly so:

• No validation of the left-hand side
• Right hand side branches:
  • If it starts with @std/: new URL(`import:${rhs}`)
  • If it starts with ./, ../, or /: new URL(rhs, baseURL)
  • Try to parse as new URL(rhs) (NB: no base URL)
  • If parsing fails, or the parsed URL's scheme is not a fetch scheme, failure

I am happy with the RHS algorithm. For the LHS, probably we should not allow the empty string? But otherwise, as discussed in some previous issues, I think it should be pretty free-form... I should probably re-read them to make sure there wasn't something I missed though.

[domenic]

Parser is merged, good to go here. The above remains accurate except now empty string specifier keys are disallowed.