cmd/internal/osinfo: report Node.js version

Seeing the Node.js version that was used during a particular test run
should be helpful during the upcoming migration from Node.js 14 to 18.
Add minimal support for that.

For #57614.

Change-Id: Id55ba25a7ee4a803788316d4a646cd4b6f4297e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/460655
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Richard Musiol <neelance@gmail.com>
Reviewed-by: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>

src/cmd/internal/osinfo/os_js.go

@@ -8,14 +8,31 @@ package osinfo
 
 import (
 	"fmt"
+	"syscall/js"
 )
 
 // Version returns the OS version name/number.
 func Version() (string, error) {
-	// Version detection on wasm varies depending on the underlying runtime
+	// Version detection on Wasm varies depending on the underlying runtime
 	// (browser, node, etc), nor is there a standard via something like
-	// WASI (see https://go.dev/issue/31105). We could attempt multiple
-	// combinations, but for now we leave this unimplemented for
-	// simplicity.
-	return "", fmt.Errorf("unimplemented")
+	// WASI (see https://go.dev/issue/31105). For now, attempt a few simple
+	// combinations for the convenience of reading logs at build.golang.org
+	// and local development. It's not a goal to recognize all environments.
+	if v, ok := node(); ok {
+		return "Node.js " + v, nil
+	}
+	return "", fmt.Errorf("unrecognized environment")
+}
+
+func node() (version string, ok bool) {
+	// Try the https://nodejs.org/api/process.html#processversion API.
+	p := js.Global().Get("process")
+	if p.IsUndefined() {
+		return "", false
+	}
+	v := p.Get("version")
+	if v.IsUndefined() {
+		return "", false
+	}
+	return v.String(), true
 }