Go 1.17 is now supported by GopherJS!! See the upstream Go 1.17 release notes for details. Noteable exceptions/differences with GopherJS:

• The GopherJS toolchain has not been updated to support lazy module loading or version suffixes for gopherjs run
• Slice to array conversion is not supported for subslices of non-linear types (https://github.com/gopherjs/gopherjs/blob/daae65060a401d321b01fef0ae7fb535230f239c/compiler/prelude/prelude.go#L178-L183)
• Outstanding compiler bugs found during the 1.17 release cycle:
  • #1063
  • #1060

This release is tested against the Go 1.17.1 standard library, although all versions of Go 1.17.x are expected to work.