XS: Map methods throw when the key argument is omitted

[d01c2]

Build environment: macOS 26.5.2

Moddable SDK version:

• Installed via jsvu, so there is no SDK source tree / git describe.
• Engine reports: XS 17.9.1, slot 32 bytes, ID 4 bytes

Target device: desktop (host xs)

Description
Map.prototype.get throws when the key argument is omitted. The same behavior occurs with Map.prototype.has, Map.prototype.delete, and Map.prototype.set.

An omitted argument supplies undefined, which is a valid Map key, so these methods should behave as if undefined were passed explicitly.

Steps to Reproduce

$ xst -e "Map.prototype.get.call(new Map());"
TypeError: no key (in Map.prototype.get)

Expected behavior
undefined is returned without an exception.

For comparison, V8 (15.3.27):

$ v8 -e "print(String(Map.prototype.get.call(new Map())))"
undefined

Other information
XS already produces the expected result when undefined is passed explicitly:

$ xst -e "print(String(Map.prototype.get.call(new Map(), undefined)))"
undefined